Send Cold Email Without Getting Blocked

Emails are one of the oldest and most commonly used methods of communication. In fact, over 319.6 billion emails are sent every day! However, not all emails are created equal. Some are personal messages between friends or family, while others are promotional messages from businesses trying to reach new customers.

In your case, you may be looking to send a cold email, or an email to someone who doesn't know you, in order to promote your business or product. It is crucial to understand that there are risks associated with this type of email—if done wrong, your message could be considered spam, and you could get blocked.

This article will serve as a comprehensive guide on cold emailing, outlining what you need to do (and not do) to ensure your message gets delivered and doesn't get you into hot water.

What is a cold email?

Let's get the basics out of the way before we get to the heart of the matter. A cold email is an unsolicited message sent to someone without prior contact. This type of email is commonly used in business settings to reach potential customers or partners. Setting up a cold email campaign can be a great way to get your foot in the door with a new client. 

For example, imagine you are the owner of a small business that specializes in website design. You find a company whose website is in dire need of a redesign and decide to reach out with a cold email. You explain your services and provide a portfolio of your previous work in the hopes that they will be interested in working with you.

What is deliverability?

Due to the fact that cold emails are unsolicited, they come with a bit of a risk. In the past, bad actors have abused email as a way of spamming people with unwanted and often harmful messages. To combat this, email providers (like Gmail, Yahoo, and Outlook) have implemented a number of measures to try and stop spam emails from reaching users' inboxes.

That's where deliverability comes in. Deliverability is the likelihood that your email will actually reach the inbox of the person you are trying to contact. In order for an email to be considered deliverable, it must first pass a series of tests set forth by the email provider. In today's guide, you'll learn about the main factors determining deliverability and what you can do to ensure your messages get through.

Benefits of cold emails

Lastly, let's look at some benefits. One of the main advantages of cold emailing is that it doesn't require a large budget. You don't need to spend money on ads or other marketing materials. All you need is an email account and a list of potential customers.

Cold emailing can also be a great way to reach decision-makers who are difficult to get in touch with. Many high-level executives are shielded by gatekeepers, making it hard to schedule a meeting or even get them on the phone. However, most people check their own email, meaning that if you can get your message in front of them, you have a good chance of getting their attention.

Finally, cold emailing can be an effective way to stand out from the competition. In most industries, there is a lot of noise and it can be hard to get noticed. However, with a well-crafted email, you can make sure that your message is seen and heard by the people who matter most.

If this strategy sounds like a good fit for your business, read on to learn more about how to send cold emails without getting blocked.

What causes you to get blocked from sending emails?

Now that we've gone over the basics of cold emailing and some of the benefits it offers, it's time to set you up for success by discussing what can cause your emails to get blocked. By understanding the main reasons for email blocking, you can avoid making common mistakes and increase the chances that your messages will be delivered.

We can split the main causes of email blocking into four categories, which we'll break down below. Note that "getting blocked" can mean either your email being marked as spam or getting blacklisted outright, which we'll discuss in more detail later on.

1. Bad Reputation

One of the most important aspects of email deliverability is your "sender reputation." Your sender reputation is essentially your emailing history, and email providers use it to determine whether or not to deliver your messages. Think of it like a credit score for email. In fact, many ISPs use a similar metric called the "Sender Score" to determine deliverability.

If your score falls below a certain threshold, your messages are more likely to be marked as spam or even blocked altogether. Many factors can influence your sender's reputation, many of which you'll find in the following sections. 

Protecting your sender's reputation should be one of your top priorities when emailing, as it's essential for maintaining high deliverability. If you think your sender's reputation might be damaged, there are a few things you can do to try and improve it. 

First, you can check your "Sender Score" at sites like This will give you a good idea of where you stand and what areas you need to work on. You can also try reaching out to the ISP directly to see if there's anything you can do to improve your reputation. In some cases, they may be able to whitelist your IP address or make other changes that will help get your messages delivered.

An IP address is a unique set of numbers that identifies a device on the internet. When you send an email, it's sent from your IP address. Keep in mind that two IP addresses are involved in every email: the sender's IP address (yours) and a domain's IP address. Domain IP addresses route emails between servers, usually different from the sender's IP address.

For example, when you send an email from Gmail, your message is actually sent from Google's servers. So, while your personal IP address might be blacklisted, Google's domain IP is almost certainly not. This is one reason why it's often best to use a professional email service like Gmail, Outlook, or Yahoo Mail when emailing contacts: it gives your messages a better chance of being delivered.

2. Bad trigger words and spammy content

Your sender's reputation is like a report card for your emailing habits, while each email you send is like a test. Just as you need to get good grades on tests to get a good report card, you need to send good emails to maintain a good sender reputation. Obviously, there is not a Google employee manually grading each email you send. So, how do ISPs determine whether an email is legitimate?

Email providers use a variety of signals to determine whether or not an email is "good" or "bad." They scan messages by using things like filters and machine learning algorithms to look for red flags that indicate spam. Here's what they're looking for:

First and foremost, you must ensure that your email messages aren't spammy. This might seem like a no-brainer, but it's one of the most common reasons people get their emails blocked. If your emails look like spam, they're more likely to be marked as such. There are certain trigger words, such as "free," "win," and "sale," that can automatically trigger spam filters.

In general, it's best to avoid using these words in your subject lines and email copy, especially if you're emailing someone for the first time. You should also avoid using all caps or excessive punctuation, as these can trigger spam filters.

Always proofread your messages before sending them, and try to make them sound natural and professional. Additionally, you must be careful about your messages' overall tone and content. If your emails are full of typos or grammatical errors or just sound "spammy," they're more likely to be marked as such.

If you're unsure whether your email is too spammy, you can always use a tool like Mail-Tester to check it. This software will scan your email as a provider would and give you a spam score as well as a list of any potential problems.

3. Not warming up your email account

If you're operating from a brand new email account, you need to take some time to "warm it up" before sending out a bunch of emails. That means gradually increasing the number of messages you send over some time. Otherwise, your account is more likely to get flagged for suspicious activity.

That's because real, legitimate email accounts are gradually built over time. So, if you're sending many messages from a brand-new account, it looks suspicious.

How long you need to warm up your account depends on how many emails you plan to send. If you're only planning on sending a few messages, you can probably get away with doing it over the course of a week or so. But if you're planning on sending hundreds or even thousands of emails, it might take a month or more to warm up your account safely.

In order to warm up your account, the messages you send should gradually increase in volume over time. They should ideally receive some sort of engagement, such as replies, clicks, or forwards. It helps to show that your messages are not only going to real people but that those people are interacting with them.

Plenty of warm-up services exist to help you with the process. All you need to do is give them your email account credentials, and they'll take care of the rest, gradually increasing the number of messages sent from your account until it's "warmed up."

4. Not including your unsubscribe link

Most of us have opted out of an email list at some point in time. It's usually pretty simple—you just scroll to the bottom of the message and click on the "unsubscribe" link. However, if you're sending emails without an unsubscribe link, you're not only setting yourself up for potential spam complaints, but you're also breaking the law.

The CAN-SPAM Act, passed in 2003, requires all commercial email messages to include a way for recipients to opt-out of future messages. So, if you're sending any promotional or marketing email, you need to ensure an unsubscribe link is included.

Additionally, your unsubscribe link must be prominently displayed and easily found. It should ideally be included in the header or footer of your message so that recipients can easily find it no matter where they are in the email. When you think about it, it's also better for them to be able to unsubscribe with one click rather than having to report your message as spam.

5. Sending too many emails over the quota of the email provider

If you're sending out a large number of emails, there's a chance you could exceed the daily or hourly limit set by your email provider. When this happens, your messages will start bouncing back as undeliverable. Avoid this unfortunate situation by keeping an eye on your account's "sending activity" so that you're not exceeding the limit.

Additionally, some providers will throttle your account if you exceed the limit, which means they'll temporarily restrict your ability to send messages. In some cases, this could even lead to your account being suspended. So, it's definitely something you want to avoid.

Different providers have different limits, so it's impossible to say exactly how many messages you can send before you start running into problems. In the case of Google, there is also a disparity between their personal and business Gmail accounts—personal Gmail accounts have a limit of 500 recipients per day. In contrast, business Gmail accounts have a limit of 2000.

Remember that even accidentally exceeding the limit can cause problems, so it's always best to err on the side of caution and keep your sending volume low until you're sure your account can handle it.

6. High bounce rates

Next up, we have bounce rates. A "bounce" occurs when an email can't be delivered for some reason—usually because the address is invalid or the mailbox is full. In fact, there are two types of bounces: hard bounces and soft bounces.

A hard bounce is when an email can't be delivered because the address is invalid or the mailbox doesn't exist. It usually happens because the recipient has moved or changed their email address without updating their contact information.

A soft bounce, on the other hand, is when an email can't be delivered because the mailbox is full or the server is down. These bounces are usually temporary and will resolve themselves after a certain time.

Ideally, you want to keep your bounce rate as low as possible. A high bounce rate looks bad and can hurt your deliverability. If you see a lot of bounces, it's a good indication that something is wrong with your list. It could be that you're using an old list that hasn't been updated in a while or that you're targeting people who are no longer interested in your product.

In either case, it's important to clean up your list regularly to ensure that you're only sending emails to people who can receive them.

7. Not having SPF DKIM and DMARC set up

SPF, DKIM, and DMARC are all authentication protocols that help to ensure that your emails are not being spoofed or phished. They work by verifying that the sender's domain matches the email's domain, which helps prevent fraudsters from impersonating your brand.

SPF stands for "Sender Policy Framework" It's a protocol that allows you to specify which IP addresses are allowed to send an email on your behalf. This helps to prevent spoofing, which is when someone uses your domain to send spam or phishing emails.

DKIM, on the other hand, stands for "DomainKeys Identified Mail" It's a protocol that uses cryptographic authentication to verify that an email was indeed sent from the domain listed in the sender information.

DMARC stands for "Domain-based Message Authentication, Reporting & Conformance" It's a protocol that builds on SPF and DKIM by adding a reporting layer. You can decide what to do with emails that fail DMARC authentication, such as flagging them as spam or rejecting them outright.

Now is the time to start if you're not already using SPF, DKIM, and DMARC. These protocols are essential for ensuring your emails' safety and security and can also help improve your deliverability. We'll go over all three of these protocols in more detail below, but just know that a combination of all three is the best way to protect your emails from being spoofed.

8. Sending emails with multiple recipients

Finally, bad emails can result from sending to multiple recipients at once. Sometimes you might need to send an email to multiple people, but it's important to be careful about how you do it.

The main problem with sending emails to multiple recipients is that they can be spammy. A generic email that's sent to a large number of people is more likely to be flagged as spam than a personal email that's sent to just a few.

Additionally, if you're sending an email to multiple recipients who don't know each other, it's important to use the "Bcc" field rather than the "To" field. The "Bcc" field stands for "blind carbon copy." This means that the recipients will not be able to see each other's email addresses, which helps to protect their privacy.

How to set up your email account to not get blocked

As you can see, successfully sending cold emails is more complicated than just crafting a great message. There are a lot of technical details that you need to take care of to ensure that your emails are delivered.

Fortunately, there are some steps you can take to make sure your email doesn't get blocked. By following these best practices, you can increase the chances that your cold emails end up in the inbox:

1. Set up good email infrastructure

We recommend starting with a reputable email provider, such as Google Workspace or Microsoft 365. These providers have robust email infrastructure to help ensure your emails are delivered successfully. Remember that using all three records (SPF, DKIM, DMARC) can help improve your deliverability.

Setting these records up isn't nearly as complicated as it sounds. In most cases, you can simply add a few lines of code to your DNS settings, and you're good to go. If you need help, your email provider should be able to assist you. Here are the basic instructions for setting up SPF, DKIM, and DMARC records with Google Workspace:


Since SPF pertains to which IP addresses are allowed to send an email on behalf of your domain, you'll need to specify the IP addresses of any servers that will be sending the email. 

Start by gathering a list of all the IP addresses that will be used to send the email. This can include your personal computer, any company servers, and any third-party services that you use to send emails (such as Mailchimp or Sendgrid).

Next, do the same for every domain that you own. If you want to be able to send emails from both and, then you'll need to create two SPF records—one for each domain. Finally, generate the code for your SPF record and add it to your DNS settings. The text should be under 255 characters and look something like this: v=spf1 ~all. 

Google Workspace has a handy tool to help you copy and paste the code into your DNS settings.


DKIM works as an authenticator for security purposes. When you set up DKIM, you're telling the receiving server that it's okay to trust email from your domain. To set up DKIM, you'll first need to generate a public and private key pair. You can use either 2048-bit or 1024-bit keys, but we recommend using 2048-bit keys for maximum security.

You'll then need to add a TXT record to your management console. Note that this record will be much longer than your SPF record—it could be several hundred characters. Once you've added the DKIM record, you can add them to your admin console and enable DKIM authentication in the settings. Finally, test your setup to make sure everything is working properly.


The last step is to set up a DMARC record, which will specify what to do with any email that doesn't pass SPF or DKIM authentication. Essentially, you can tell the receiving server to either accept, quarantine or reject these emails. Here is also where you enter the email address you want to receive DMARC reports.

Like DKIM, setting up DMARC requires you to generate a TXT record and add it to your admin console settings.

We dedicated an entire article to email authentication if you need more information on any of these steps. Feel free to check it out for more detailed instructions.


One step people often overlook is the process of ensuring that their email profile is up-to-date and accurate. In the case of Google Workspace (AKA G Suite) your profile includes your name, title, photo, and contact information. It may seem like a no-brainer, but you'd be surprised how many people have out-of-date or inaccurate profiles.

An email signature is also a great way to add professionalism and personality to your emails. A signature should include your name, title, company name, website, social media links, and contact information. Add an address or PO Box if you want people to be able to send you physical mail. 

If you want to get really fancy, you can create a custom email signature using HTML code. This signature allows you to add graphics, links, and another formatting that might not be available in the signature editor. Just be careful not to overdo it—a signature that's too long or too complicated can be a turn-off for recipients.

As for Gravatar, or Globally Recognized Avatar, it is becoming increasingly common for websites to display a user's Gravatar image next to their name. A Gravatar is essentially a profile picture that follows you around the web. 

If you have a Gravatar image associated with your email address, it will likely be displayed next to your name whenever you leave a comment on a blog or forum. It might be a good idea to set up a Gravatar image for your business email address to display your name and photo consistently across the web.

2. Warmup your inbox via Warmup Inbox

One of the best ways to avoid the spam folder is to start sending emails before you need to. As mentioned above, warming up your inbox gradually increases the volume of emails you send from a new account. It helps you build a reputation with ISPs and avoid getting flagged as spam. is a great tool for warming up your inbox. Simply create an account, add your sender information, and choose how fast you want to ramp up your sending volume. The service automatically sends emails on your behalf, increasing the volume over time. has a network of over 20,000 real inboxes that you can use to send your emails. Warmup Inbox is a great way to start email marketing without worrying about getting flagged as spam.

Once you've built up a reputation, you can start regularly sending emails to your list. Just keep an eye on your open and click-through rates to ensure your emails are getting through.

3. Add a custom domain to your sending account in Mailstand

Another great way to improve your deliverability is to add a custom domain to your account. That means sending your emails from a domain that you own rather than a generic Gmail or Hotmail address.

Mailstand is a great tool for adding a custom domain to your sending account. Simply create an account, add your domain name, and then follow the instructions to verify your ownership. Once your domain is verified, you can start sending emails from your custom address.

Adding a custom domain to your account is a great way to improve your deliverability and show recipients that you're a legitimate sender. You can use to use multiple mailboxes from your custom domain, which is great for larger businesses. Every address will have its own inbox, so you can easily keep track of all your email correspondence in one place.

It also helps with your branding since recipients will see your custom domain name instead of a generic email address. Use it to A/B test different subject lines, sender names, and email content to see what gets the best results.

4. Send Personalized 1 to 1 Emails

Remember, the goal is to get more replies, not just more opens. So, don't just rely on Marketing Automation or a tool to do the job for you. Take some time out of your day to send a few personalized messages to people from your target market. It could be a potential customer, client, or partner. Just make sure it's someone who is likely to respond.

Address them by name, mention something you have in common, or reference a recent interaction. The key is to make it personal so they feel like you're actually reaching out to them, not just sending a generic email. Personalized emails have a much higher chance of getting replied to, so it's worth taking the time to write them.

And if you're worried about scale, don't be. Plenty of tools can help you personalize your emails at scale. By using placeholders such as <First Name> or <Company>, you can insert personalized information into your emails without having to write each one individually. Simply upload your contact list and let the tool do the work for you.

Sending personalized 1-to-1 emails is a great way to improve your deliverability and get more replies from your target market. It's also a great way to build relationships with potential customers, clients, and partners.

5. Verify your email address before you send out emails

You'll be asked to verify your email address upon signing up for an email account. This verification is done by clicking a link in your verification email. Once you click the link, your email address will be confirmed, and you'll be able to start sending and receiving emails.

However, if you don't verify your email address, you won't be able to use it to send or receive any emails. That means any messages you try to send will bounce back, and you won't be able to see any messages sent to you.

So, if you're planning to send out any emails, verify your email address first. It only takes a few seconds, and it'll ensure that your messages are delivered successfully. It also allows you to recover your account if you ever forget your password.

6. Send only 50-200 emails per day per inbox through Mailstand

Finally, keep an eye on your email sending limit. allows you to send up to 200 emails daily, but we recommend keeping it at 50-100 to avoid potential deliverability issues. It can be easy to lose track of how many emails you're sending, especially if you're using a tool to automate your email marketing.

How many emails can I send without getting blacklisted?

Although this seems like a straightforward question, there is no easy answer. It depends on various factors, such as your email list quality, the content of your emails, and your sending frequency.

Generally speaking, a bounce rate over 10% is cause for concern, and a click-through rate below 2% is considered poor. If you regularly hit these thresholds, you're at risk of being blacklisted.

It's also important to keep an eye on your complaint rate. This is the number of people who mark your emails as spam. If this number starts to swell, it's a sign that your emails are being marked as spam more often. Finally, it's worth noting that some email providers have stricter sending limits than others. But that doesn't mean you should aim to reach those limits.

The best way to avoid being blacklisted is to focus on delivering quality emails that people actually want to receive. If you're regularly hitting the spam folder, it's time to take a step back and reevaluate your email strategy.

We recommend sending 50-200 well-crafted emails daily to avoid potential deliverability issues. If you're sending more than that, you're at risk of being marked as a spammer(i.e., blacklisted). And if you're sending less than that, then you're not making the most of your email list. 


That's it! We've reached the end of our cold email deliverability guide. By now, you should have a good understanding of how to send cold emails without getting blocked. Just remember to focus on quality over quantity, and you'll be well on your way to success. 

Take care of all the technical stuff at the beginning (like setting up DKIM and SPF records and warming up your domain), and the rest will fall into place.

Once you're ready to go, all that's left to do is craft good cold emails by respecting the best practices we've talked about. If you can do that, then you'll be well on your way to building relationships with potential customers, clients, and partners.

Try Mailstand for free.

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