How to troubleshoot when a message has bounced from an ISP due to content or URL being blacklisted
When you send a message to an ISP (Internet Service Provider) or an ESP (Email Service Provider), their Spam filters check your message to make sure it does not contain Spam. ISPs may also check with other databases that maintain lists of URLs (web page links) and content that have been used by spammers before. Such lists are called blacklists.
If the message content triggers the ISP's Spam filter, then your message may not reach your subscriber. It may get bounced back to us. In that case, we send you a notification message. That notice will usually contain the error message. The error details can provide clues about which URL/content was responsible for the message rejection.
Our system that sends you the notification is known as the Bounce Re-Delivery System (BRDS).
To help with this process, we have included some tips below to help you troubleshoot such issues on your own.
Bounce Error Log
Here is an example of a log, which contains the bounce error. This log would be included in the email that our BRDS system sends you when your message bounces.
The log should give you enough clues to troubleshoot on your own. In case it doesn't, please follow the steps below to find which common blacklists contain the URL used in your message.
If the URL is not important and you don't plan to use it in your subsequent messages, then maybe you don't need to troubleshoot any further. Simply exclude that URL in future messages.
Where to Check for Blacklists
Start here - Email Blacklists 101: What You Need to Know
Usually the bounce error message will give you hints about which URL and/or blacklist was used to check your message.
Once you determine which blacklist company caused the message rejection, you need to contact that company. Each company has procedures to follow to get your URL/content removed from the blacklist.
If the URL that is causing the problem is not yours, then we recommend not to use it again. If it belongs to your organization, then you need to report it to the blacklist company directly.
If the bounce error message indicates the problem is with the message content, it may give you hints about which words to avoid using in your messages.
How do URL's get blacklisted?
A URL can end up on a blacklist for several reasons:
- Spammers have used the URL.
- The URL was used in a message that many users reported as Spam.
- The URL is known to have phishing links/malware.
- Internet security software or search engines have reported finding irregularities on the URL's destination website.