I am using plesk mail server, I am use outlook 2013, installed on windows 7. No matter what I try, I can’t get outlook to send email through my mail account. I keep getting the error: your server does not support the connection encryption type you have specified.
TLSv1, SSLv3 or SSLv2 protocol support, which is required for old email clients/old software (e.g, WinHTTP-based applications on Windows 7) is disabled in Postfix/Dovecot configuration.
The best practice is to use the latest available version of email clients that support connections over TLS 1.1 and 1.2.
For WinHTTP-based applications, refer to the Microsoft article.