FAQs - Why is my IP address or domain blocklisted?

❗️ Important
This article is for users on a dedicated IP. If you're on a shared IP and believe it has been blocklisted, contact our support team for further investigation.

When your IP address or domain ends up on a blocklist, emails sent to that provider start bouncing instead of reaching the inbox. This article explains what a blocklist is, why it happens, how to check your status, and how to request removal.

What is a blocklist?

A blocklist is a collection of IP addresses or domain names that are blocked by Internet Service Providers (ISPs) or anti-spam solutions because they are suspected of engaging in suspicious activities, such as spamming, phishing, or generating high hard bounce, unsubscribe, complaint, or spam trap rates. When your IP address or domain name appears on a blocklist, it means it has been flagged as potentially harmful.

There are two types of blocklists:

  • ISP blocklist
    If an Internet Service Provider (ISP) blocklists your IP address or domain, emails sent to addresses using that ISP's domain (e.g., gmail.com or outlook.com) will soft bounce.
  • Anti-spam blocklist
    Anti-spam solutions are commonly used by businesses and professionals to provide an additional layer of protection against spam. If an anti-spam solution blocklists your IP or domain, emails will soft bounce when sent to recipients using that solution.

Why is an IP address or domain blocklisted?

Most of the time, an IP address or domain is blocklisted because it is suspected of engaging in suspicious activities, such as spamming, phishing, or generating high hard bounce, unsubscribe, complaint, or spam trap rates.

Expand the following accordions to view some of the most common reasons why this might happen:

You may be sending unsolicited emails

The most common reason for being blocklisted is that ISPs flag your emails as unsolicited or spam. This can happen if:

  • Your content appears spammy.
  • You're sending to purchased or outdated contact lists.
  • Your recipients mark your emails as spam.
You are sending to unengaged or inactive contacts

Make sure you send emails to engaged contacts who have explicitly agreed to receive your communications. This helps generate positive metrics like opens, clicks, forwards, and replies while reducing the risk of spam traps, unsubscribes, hard bounces, and complaints.

Your bounce or complaint rates are too high

ISPs monitor bounce rates and spam complaints. If too many of your emails are rejected or reported as spam, your sending reputation may be negatively impacted, leading to your IP address or domain being blocklisted.

💡 Good to know
Some ISPs, like Gmail and Yahoo, have a complaint threshold of 0.3%, meaning even a small number of complaints can negatively impact your sender reputation.
You did not properly warm up your dedicated IP
❗️ Important
If you haven't sent emails from your dedicated IP in the last 30 days, you need to restart the warm-up process.

ISPs may blocklist your IP if you send too many emails too quickly from a new or inactive dedicated IP. Proper warm-up builds your reputation as a trusted sender.

➡️ To learn more, check our dedicated article Warm up your dedicated IP (manual warm-up) or Warm up your dedicated IP (automatic warm-up).

You're sending emails to spam traps

Spam traps are email addresses used to identify spammers and senders who don't follow best practices. Sending emails to these addresses can lead to blocklisting.

➡️ To learn more, check our dedicated article What are spam traps and how to avoid them?

You have been blocklisted by mistake

Even if you follow best practices, your IP address or domain may still be mistakenly blocklisted. This sometimes happens when an IP is flagged for suspicious activity, leading to similar IPs or domains being blocklisted as well.

💡 Good to know
Some ISPs, such as Microsoft, are more sensitive to false positives and may blocklist new IPs even if they have a good sender reputation.

How do I know if my IP address or domain is blocklisted?

If your IP address or domain is blocklisted, you will typically notice a high number of soft bounces from a specific domain in Brevo. To confirm whether your IP or domain has been blocklisted, you should:

Step 1: (Optional) Use an external tool to scan against blocklists

❗️ Important
Not all blocklists are listed in these external tools. Major providers like Gmail and Yahoo have private blocklists that won't appear in public databases. You should still follow steps 2 and 3 to get more detailed information about your blocklist status.

If you want to quickly check, or as part of your regular deliverability routine, you can use an external tool to scan major and minor blocklists. Several online tools offer a quick overview:

Step 2: Check your campaign report in Brevo for soft bounce details

From Marketing > Campaigns > Statistics, open a campaign report and access the Deliverability tab to view detailed information about soft bounces:

deliv_blocklist_deliverability-tab_soft-bounces_en-us.png

  1. Soft bounce statistics
    • Check the number and percentage of soft bounces for your campaign.
    • Click View to access the list of contacts whose emails resulted in a soft bounce.
    • Check the associated error messages from each contact's details page in step 3.
  2. Soft bounce reasons
    Understand why your emails soft-bounced. If you see "The domain or IP blocklisted", it means your IP or domain has been blocklisted.

  3. Soft bounces by domains
    Identify which domains caused a high number of soft bounces. 

    ✅ Plan availability
    The Deliverability breakdown by domains feature is only available on the Standard, Professional, and Enterprise plans. For more information, check our pricing page.

Step 3: Check the error messages associated with the soft bounces

When an email soft bounces, the ISP returns an error message. You can review these messages to identify who blocklisted your IP address or domain and request removal.

  1. From Marketing > Campaigns > Statistics, open a campaign report and access the Deliverability tab.
  2. In the Deliverability details section of a campaign report, click View next to the Soft bounces statistic. The list of contacts whose emails resulted in a soft bounce opens.
    deliv_blocklist_deliverability-tab_soft-bounces_view_en-us.png
  3. (Optional) In the search bar, enter the name of the domain that caused a high number of soft bounces. This helps filter results to find bounces related to blocklists.
    deliv_blocklist_soft-bounces_contacts_en-us.png
  4. Click a contact from the list to access their details.
  5. Under the Email event of the email that bounced, click Show details. If the bounce is due to a blocklist, the message often includes terms like "blocklist" or "banned IP" and may provide a direct link to request removal. For example, here's an error message from Microsoft:
    deliv_blocklist_soft-bounce_microsoft_error-message_en-us.png

How can I get removed from a blocklist?

❗️ Important
  • Only the owner of the IP or domain can request removal. Brevo support cannot remove IPs or domains from external blocklists.
  • Asking an ISP or an anti-spam solution to remove you from their blocklist doesn't guarantee that they will do it.

Blocklisting reasons vary by IP address or domain, so there is no universal removal process. Before requesting removal, identify the root cause and take corrective action.

  1. Identify the root cause
    • When did the issue start?
    • Are you sending from a new IP address or domain?
    • Have you recently increased your sending volume?
    • Are you receiving high complaint rates, hard bounces, or unsubscribes?
    • Are you sending emails to new or unengaged contacts?
  2. Fix the issue
    • Stop sending emails to blocked ISPs or recipients using the anti-spam solution that blocklisted you. Continuing to send to these recipients can further damage your sender reputation and delay the delisting process.
    • Improve contact segmentation to only send to engaged recipients.
    • Clean your contact list by removing inactive or unengaged users.
    • Warm up your IP again if you took a break from sending.
    • Reduce your sending volume and gradually rebuild your reputation.

➡️ If your IP or domain is blocklisted by a specific ISP, check the dedicated troubleshooting article for more information:

How to avoid being blocklisted again?

After your IP or domain is removed from a blocklist, it's important to follow best practices to prevent future issues and maintain a good sender reputation. Here are some essential steps to keep your email deliverability healthy:

  • Follow our best practices for managing a dedicated IP to maintain optimal inbox placement and a strong reputation.
  • Send emails only to contacts who have explicitly subscribed and expect to hear from you.
  • Segment your contacts based on their interests to send relevant content and increase engagement.
  • Regularly clean your contact list to remove unengaged or invalid email addresses.
  • Encourage your recipients to add your email address to their address book, which helps your emails be seen as personal communication by ISPs.
  • Avoid using URL shorteners, as they are commonly associated with spammers and can affect deliverability.
  • Regularly check your blocklist status to ensure you're not on a blocklist.
  • Warm up your IP again if you've taken a break from sending, and gradually increase your sending volume to rebuild your reputation.

By consistently following these practices and monitoring your metrics, you can reduce the risk of getting blocklisted in the future.

⏭️ What's next?

🤔 Have a question?

If you have a question, feel free to contact our support team by creating a ticket from your account. If you don't have an account yet, you can contact us here.

If you’re looking for help with a project using Brevo, we can match you with the right certified Brevo Agency partner.

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