Mail Immediately forgets SMTP Password I'm trying to set up Apple Mail to send through my web host's SMTP server (not Gmail, or any common email provider), and as soon as I save the SMTP settings, Mail forgets the password, meaning that authentication always fails. I type the password in the dialog below, click OK, and then reopen the "Edit SMTP Servers" dialog, and the password is gone.

This seems to happen only for this SMTP account. Others work just fine. I've tried removing the password from Keychain, repairing Disk Permissions, and completely removing all of my Mail data, but Mail still forgets my password immediately. Authentication doesn't even succeed once.

How can I get Mail to remember my SMTP password? I'd rather not completely reset my Keychain, so I'm looking for any other suggestions.
I'm experiencing a similar issue. I've been doing some reading throughout the morning, and one possible solution I've found was covered here: http://osxdaily.com/2015/07/05/resolving-mail-problems-os-x-update/

Disabling 'automatically detect and maintain settings' seems to have cleared it up for me, however I'm not 100% sure that this will be your solution, as your screenshot shows that box already unchecked.