Note on OSX Yosemite mail smtp setting
This is a nerdy, note-to-self blog entry.
When upgrading a mac to OSX 10.10 Yosemite, I found that OSX Mail.app can change the preference for outgoing smtp servers.
In Mavericks and earlier, there was a setting 'use default ports' which would result in the outgoing server trying three ports: 587, 465 and plain ole' 25. The name of the mailserver I used was 'smtps.domain'. (an old alias, it turned out, but still working). Note the s.
After converting to Yosemite, mail would occasionally have trouble connecting to the smtp server. It turned out it had converted the setting to the fixed port number 587. For this server it turned out it had to be 465.
So, trouble sending mail after upgrading to OSX Yosemite check the SMTP-serverlist in Mail preferences (under account, outgoing server, click on the popup-list, then 'manage smtp servers').