BL000000: blocked for spam-like sending patterns

What it means

BL000000 is Xfinity's own block, apart from the public blocklists behind its other BL codes. Its filters judged that mail from your server's IP address followed patterns typical of spam, and refused further mail from it to protect Xfinity customers. Because many users can share one mail server, the cause may be someone else on the same server. To have it lifted, submit a removal request on the Customer Security Assurance Postmaster site with the IP address of the blocked server, which appears in the error message. Xfinity says these requests are monitored 24 hours a day, seven days a week.

Common causes

• Your server sent a burst of mail, or mail with traits, that Xfinity's filters read as spam.
• Another user or customer sharing your mail server sent spam.
• A compromised account or script on the server sent mail without your knowledge.

How to fix it

1. 01Find the blocked IP address in the error message and keep the full error text.
2. 02If you use a provider, send them the complete error so they can find and stop the source.
3. 03If you run the server, check the outbound queue and logs for spam or a compromised account, and fix it before asking for removal.
4. 04Submit a removal request on Xfinity's Customer Security Assurance Postmaster site with the blocked IP address.
5. 05Once the block is lifted, resume sending to Xfinity addresses at a moderate pace.

Sources

What this page rests on, checked on 20 Oct 2026. The explanation is ours; the reply text is the server's.

• Troubleshoot Comcast.net email error codes (Xfinity)xfinity.com

Further reading

• Blacklist checker
• How to know if you are blacklisted