Hello,
dovecot has no config for ssl
ssl_cert = </etc/dovecot/private/dovecot.pem
ssl_key = </etc/dovecot/private/dovecot.key
Also no Security settings:
#ssl_dh_parameters_length = 1024
#ssl_protocols = !SSLv3
#ssl_cipher_list = ALL:!LOW:!SSLv2:!EXP:!aNULL