SMTP SSL Authentication issues with outlook 2007 (Plesk, using IMAP)
Some Outlook 2007 IMAP users have reported issues authenticating to our Plesk mail servers to send mail.
with an error: "This client does not support any of the authentication methods used by this server"
Here is a fix around this issue:
Display your account's outgoing mail (SMTP) settings in Outlook:
click on the Tools menu, then Account Settings
Select your email account, and under the Outgoing Server tab
leave My outgoing server (SMTP) Requires Authentication checked
change security to TLS (instead of SSL)
change port to 587 (instead of 25)
This will allow you to authenticate with our servers.