Important when an email account has been deleted!

If you delete an email account in our control panel, you need to remove the existing transport (POP3, SMTP, IMAP) in your email client too, otherwise the email client will try to log in with incorrect (non-existent) login data and the firewall will block your connection due too many fail logins.
It is therefore required to remove the transport in your email clients for non-existent email accounts!