I´ve started to test Zimbra with outside mails. Things seem to be working quite well, except that any email sent from a GMAIL account returns the following undelivered message:
Delivery to the following recipient failed permanently:
Technical details of permanent failure:
Google tried to deliver your message, but it was rejected by the recipient domain. We recommend contacting the other email provider for further information about the cause of this error. The error that the other server returned was: 500 500 5.3.3 Unrecognized command (state 9).
If I send an email to Gmail it is delivered. I am just unable to receive from a Gmail account, they all bounce back. I have also added the gmail.com domain to the whitelist.
Yahoo, Hotmail and other accounts do not have this problem.
I appreciate any comments.
Thank you in advance,