zmprov getServer `zmhostname` | grep zimbraMtaAuthEnabled It should return TRUE . If you’ve configured a “Send As” alias (e.g., sending as @gmail.com from your Zimbra webmail), Zimbra will reject it unless you’ve explicitly allowed it.
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. zimbra relay access denied
It usually appears without warning. One minute, a user or an application is sending mail fine; the next, emails are bouncing back. Don’t panic. This error is actually Zimbra’s security system doing its job—it just needs a little adjustment. zimbra relay access denied