Domain Blacklisting

In this article we will observe some of the potential cause for a domain to be blacklisted and some of the recommendations on how you could improvise them. 

What causes a domain to get into a blacklist

  • Receiving spam complaints

If the recipients of your email flag it as spam, then the mail providers will think that it is true and it is not of value to the prospect. 

Even if your list is clean and opted in, a click on the ‘mark as spam’ button will count as a spam complaint. 

The more complaints you receive, the more likely it is for your  domain to be added to a blacklist.

  • Acquiring bad email lists or addresses

When your campaigns have a high bounce rate (above five percent) due to bad quality lists, the recipient email provider think that your list may not be opted-in or current. 

Also, if you send emails to spam bait addresses, then that will get you onto an email blacklist.

  • Sending identical emails / Email Blasting

Whenever you send close to identical emails to lots of people, that also triggers the spam signals. 

Emails that are not personalized are categorized as spam with no valuable content for the recipient.

  • Abusing daily sending limits / Spam sending rates and volumes

Users that send a big amount of emails per day will raise the alarms for recipient email provider

Also, if the interval between those emails is non-existent or identical, then it will also be considered spam.

How to avoid getting into blacklist

  • Avoid spam email content

There are keywords that are highly associated with spam and should be avoided. 

Some words include ‘free’, ‘money’, ‘risk free’, ‘apply now’, etc. 

  • Watch your email campaign’s bounce rate (For the subscription of email marketing service) 

A quick way to get your domain on an email blacklist is by having a high bounce rate. 

Ensure you have a process of regularly validating the data and checking to see if the email addresses are still active. 

In your campaigns, remove the bounced addresses to avoid sending follow-ups to them. 

  • Adapt your sending volume and intervals

If you send too many emails per day at the same time, then you are likely to end up on an email blacklist sooner or later.

So, keep the number of sent emails below 100 per day per mailbox. 

  • Ensure the domain is equipped with DMARC, DKIM and SPF records

DMARC, which stands for “Domain-based Message Authentication, Reporting & Conformance”, is an email authentication, policy, and reporting protocol. 

It builds on the widely deployed SPF and DKIM protocols, adding linkage to the author (“From:”) domain name, published policies for recipient handling of authentication failures, and reporting from receivers to senders, to improve and monitor protection of the domain from fraudulent email.

DomainKeys Identified Mail (DKIM) helps protect email users against email address identity theft and email message content tampering. 

It does this by providing positive identification of the signer’s identity along with an encrypted “hash” of the message content.  

SPF (Sender Policy Framework) is an anti-spoofing technique that determines if an incoming email from a domain was sent from a host that is authorized to send mail for that domain.

Please reach our support to verify shall your domain is equipped with DMARC, DKIM and SPF records.


Please be advised that your domain could be still blacklisted even with the above implementation due to the blacklisting is controlled by the recipient external provider which is out of our control.

Did you find it helpful? Yes No

Send feedback
Sorry we couldn't be helpful. Help us improve this article with your feedback.