[Dovecot] TLS Issue

Hi,

I use Postfix & Dovecot with TLS / SSL - it authenticates / works fine - except I'm always getting this ugly SSL cert warning messages mit MTAs. It says that the following:

"You have attempted to establish a connection with "server". However, the security certificate presented belongs to "*.server". It is possible, though unlikely, that someone may be trying to intercept your communication with this web site."

Is there a serverside solution that I wont get that any more? Why is * as a wildcard not working? Iwonder How gMail or other providers solve that issue

Regards