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Outbound email from Email is rejected or blocked due to blacklists


Article ID: 169901


Updated On:




A user who sends email through Symantec Email receives a bounceback email indicating that the sending server's IP address has been blacklisted.

Common bounceback errors related to blacklisted IP addresses include:

  • I was unable to deliver your message to the following addresses
  • connect to 550 Connection refused - we hate spammers!
  • host said: 554 Denied
  • host said: 552 spam source blocked

Note: These errors vary depending on the recipient's mail transfer agent (i.e. MTA, or mail server).


These errors indicate that Email attempted to deliver the message to the intended recipient’s server, but the message was rejected by the server, typically due to email blacklists.

IP addresses for may occassionly get blacklisted due to users who abuse the service by sending spam, or from compromised servers relaying spam through the email infrastructure.


Symantec proactively monitors email blacklists, and delivery problems associated with these errors are usually temporary.

To check if a specific IP address is in a blacklist, use the following 3rd-party services:

If email continues to be rejected due to blacklisted IP addresses, open a support case.

See Email infrastructure is blacklisted for more information.