On Monday 19 April 2010 09:51:52 mohamad rahimi wrote: > In our group we are using suse and > Postfix SMTP server. Every thing was fine until last month when we > restart our mail server and also firewall. > The first problem is that when we use > Thunderbird with security and Authentication it is impossible to send > a email. we receive this error “Unable to authentication to SMTP > server mx.mydomain. The server does not support any compatible > secure authentication mechanism but you have chosen secure > authentication.
Could it be that authentication depends on a daemon and that daemon isn't in your start-up scripts? But without details of how it was configured I'm just guessing. So it could be as simple as: "/etc/init.d/courier-authdaemon start" And then ensuring it is in the start-up. Post here output of postconf, and also any errors, and others can probably give more specific advice.