I am using Zimbra desktop (just switched from Thunderbird) and I am having an error. On Windows, I use an SSH client to connect to my Linux web server and map the imap server to localhost:143.

When Zimbra sends emails, I get this error:
504 5.5.2 <localhost>: Helo command rejected: need fully-qualified hostname

Now, this error is a setting that is on postfix to reduce the number of spam messages. The desktop settings are localhost. I've also even used the actual domains and mapped them to on my desktop hosts to see if that would trick it, but still get the same error.

Any ideas would be appreciated.

Thank you.