A blocklist is a collection of IP addresses or domain names that have been identified by Internet Service Providers (ISPs) or anti-spam solutions because they're suspected of suspicious activities, such as spamming, phishing, or sending emails to spam traps. Being blocklisted means that your IP address or domain name has been flagged and that your IP address or domain name has been reported on a blocklist.
There are two types of blocklists:
When blocklisted by an ISP, your emails will soft bounce when sent to a specific domain, e.g. Google or Yahoo. You can view the soft bounces per domain of a campaign by going to Campaigns > Statistics and opening a specific campaign report, and checking the By Domain tab at the bottom of the page.
When blocklisted by an anti-spam solution, your emails will soft bounce when sent to a recipient who uses an anti-spam solution that blocklisted your IP address or domain name.
Anti-spam solution blocklists are used on top of existing webmail filters in order to increase spam filtering. They are mostly used by professionals to implement more security on their systems.
How do I know if I'm blocklisted?
If you notice a high number of soft bounces from a specific domain, it could mean that you've been blocklisted. To learn how to find the error message of a bounce to see if the contact bounced because you’ve been blocklisted, check our dedicated section Where can I view why my email bounced? in What are soft bounces and hard bounces?.
You may be in a single blocklist or multiple blocklists. Each blocklist is managed independently, and each has its own criteria for blocklisting an IP address or domain name.
Why is my IP address or domain name blocklisted?
Here is a list of some of the most common reasons why you may be blocklisted:
You may be sending unsolicited emails
The most common reason for being blocklisted is that ISPs consider that you're sending unsolicited emails or spam to your contacts. This might be because the content of your emails looks spammy to the ISPs or because the contacts you're targeting have no interest in the emails you're sending them, such as contacts from a purchased list or subscribed contacts who have not engaged with your emails in a while.
If contacts have no interest in your emails, they might report them as spam. Their ISP will then notice it and could decide to blocklist you.
Learn more about cleaning your contact list and targeting engaged contacts in our dedicated article Optimize and clean your contact list to improve email deliverability.
Your IP address isn't correctly warmed up
Warming up your IP address is very important to be seen as a legitimate sender by ISPs. If your IP address isn't correctly warmed up and you immediately start sending thousands of emails at once, ISPs may suspect you and not deliver your emails to your recipients, or even blocklist you.
Learn more about how to warm up an IP address in our dedicated article Warm up your dedicated IP.
Your emails are reaching spam traps
A spam trap is an email address used to identify and filter spammers and senders who do not follow the best emailing practices and/or GDPR regulations. If your emails are reaching spam traps, they are very likely to end up in the spam folder and you could even get blocklisted.
Learn more about spam traps in our dedicated article What are spam traps and how to avoid them?.
Your IP address was blocklisted by mistake
You could also end up blocklisted even if you follow all the best sending practices. Sometimes, when an IP address is blocklisted because of suspicious activity, similar IP addresses are also blocklisted.
How can I be removed from a blocklist?
As the reasons for blocklisting are specific to each IP address or domain name, there is no global solution to be removed from a blocklist.
We highly recommend you contact our support team so that we can investigate why you are blocklisted and explain how you can ask to be removed from the blocklist.
How can I avoid being blocklisted?
Here are some good practices to follow to avoid getting blocklisted:
- Follow our best practices to ensure the best deliverability for your emails.
- Ensure that your contacts are expecting to hear from you by only sending emails to subscribed contacts.
- Segment your contacts based on their interests to make sure you are targeting the right contacts with the right content and, therefore, increase engagement.
- Regularly clean your contact list to remove any unengaged or invalid email addresses.
- Ask your email recipients to add your email address to their address book to be seen as a personal contact by ISPs.
- Avoid using URL shorteners as they're often used by spammers to hide their original URLs.
- Check your blocklist status before sending your email campaigns to make sure you're not blocklisted.