Full settings in harmattan on N9:

Secure: SSL
serveraddress: mail2.bahnhof.se
Port: 465
Verification: Standard Password

in SailfishOS on my Jolla:

Secure: SSL
serveraddress: mail2.bahnhof.se
Port: 465
Auth: Password

Hmm just think of something here:

My provider, Bahnhof, only allow SMTP when I am at my home wifi. And I am ATM. But it seems Jolla Phone is active on 3G and wifi in the same time (both icons shown on sleep screen)? Could it be that Jolla Phone try send over 3G even when Wifi is active?

Edit: tested disable 3G did not fix issue.