
Originally Posted by
phoenix
Well, I guess from your comments that you are using a mail service provided by a hosting company. You should aks them for details as we have nothing to do with it - this is a forum for users that have installed the Zimbra Collaboration Suite.
You could try setting the 'Secure Connection' to never or one of your other options and see if that works, without knowing how the server is set-up there isn't much we can do.. Doesn't your mail provider have a help page or support site?