For my mail server using Zimbra --
- IMAP with TLS/SSL enabled was the only thing that worked. Unchecking TLS/SSL caused a "no valid login methods" error
- I also needed the full username@domain.com username
- The default TLS/SSL ports worked for me (incoming 993, outgoing 465)
POP3 returned a "invalid credentials" error.
Clik here to view.
