Hello, I have a problem with my Mail Server. I installed my Web + Mail Server with this tutorial and secured my ispconfig with this tutorial. The Webserver works fine. The mail server has an issue. I can only login in Webmail (Roundcube). In Webmail i can send and recieve mails without problems. The issue is that i can't login via an external mail client like thunderbird or outlook. My mail.log says: "imap-login: Disconnected (no auth attempts in 0 secs)". Could it be a Certificate problem? I tried to reinstall the server multiple times but i doesn't solve the problem.