I repeatedly have a hell of a time getting clients' Outlook software working well with Dovecot. It's hard for me to test myself since I don't have Outlook and it would be impossible to keep up with all the different versions anyway.
I've got the following settings, currently:
disable_plaintext_auth = yes auth_username_format = %Ln auth_mechanisms = plain login ssl = yes
service imap-login { # inet_listener imap { # port = 143 # }
inet_listener imaps { port = 993 ssl = yes } }
service imap { client_limit = 1 }
It always seems to be hit or miss with outlook as to which encryption setting to use, which port to try, etc. With a recent client, I couldn't get them successfully logged in no matter what manual settings we tried. If someone can give me some tips on how to get most versions of Outlook cooperating well with Dovecot, I'd appreciate it.