Zimbra Relay Access Denied ◎ (VALIDATED)

Start with authentication (port 587). If that doesn’t work, check your mynetworks . Nine times out of ten, that resolves the issue.

If you manage a Zimbra Collaboration Suite (ZCS) environment, you’ve likely seen the dreaded "554 5.7.1 <[email protected]>: Relay access denied" error in your mail logs. zimbra relay access denied

In this post, we’ll break down why this happens and the three most common ways to fix it. An SMTP relay is when a mail server accepts a message and delivers it to a domain that is not its own. Start with authentication (port 587)

By default, Zimbra’s Postfix (the MTA underneath) is configured as a closed relay. This prevents spammers from abusing your server to send thousands of emails to Gmail or Yahoo. When you see "Relay Access Denied," Zimbra is saying: "I don’t know this sender, and I’m not responsible for the destination domain—so I’m refusing this message." If you manage a Zimbra Collaboration Suite (ZCS)