Symptoms
Receiving emails from a certain mail server fails with the following records in the file /var/log/maillog:
plesk postfix/smtpd[2501]: connect from sender.example.com[203.0.113.2]
plesk postfix/smtpd[2501]: SSL_accept error from sender.example.com[203.0.113.2]: -1
plesk postfix/smtpd[2501]: warning: TLS library problem: error:1408A0C1:SSL routines:ssl3_get_client_hello:no shared cipher:s3_srvr.c:1435:
plesk postfix/smtpd[2501]: lost connection after STARTTLS from sender.example.com[203.0.113.2]
plesk postfix/smtpd[2501]: disconnect from sender.example.com[203.0.113.2] ehlo=1 starttls=0/1 commands=1/2
Cause
The sender server uses deprecated protocol SSLv3 that is disabled on Plesk servers with Postfix for security reasons.
Resolution
It will be possible to receive emails just after the SSLv3 protocol is disabled on the sender's side.