I recently installed Zimbra and I have slowly started migrating customers. I am sure this issue is addressed somewhere in the forums, wiki, or documentation; however, after an hour of searching while customers are complaining, I thought I would just post the question in hopes of a quick answer.

Basically, I have something setup wrong - at least I think.

My customers who are using an email client, for POP or IMAP, are unable to send messages. I have even tried to configure email clients, and I cannot get the SMPT connection test to work.

For Outgoing Mail Settings, I insert my mail server into the outgoing mail server box: I.e.: mail.servername.net

I then check the "Use Authentication" box, and I enter my full username: username@domainname.com.

Obviously, in the above examples, "servername" in the outgoing mail server settings, and "domainname" in the username settings can differ as I have multiple domains configured within the GUI Admin Console for Zimbra. I currently have 30+ domains for which we host email.

Any suggestions, or can someone point me to a previous thread? For some reason I am having a heck of a time finding documentation or threads on this.

Basically, my customers currently either cannot configure their email clients, or they are getting a 554 Relay Access Denied error.