Please check whether you have correct setting for below parameters in Postfix config file (main.cf):
smtpd_tls_key_file=
smtpd_tls_cert_file=
smtpd_tls_CAfile=
And Dovecot config file:
ssl_ca =
ssl_cert =
ssl_key =
Please check whether you have correct setting for below parameters in Postfix config file (main.cf):
smtpd_tls_key_file=
smtpd_tls_cert_file=
smtpd_tls_CAfile=
And Dovecot config file:
ssl_ca =
ssl_cert =
ssl_key =