From: Roger Reporter <roger@example.org>
 To: Andy Admin <admin@example.com>
 Subject: Certificate problem?
 TLS-Required: No
 Date: Fri, 18 Jan 2019 10:26:55 -0800
 Message-ID: <5c421a6f79c0e_d153ff8286d45c468473@mail.example.org>

 Andy, there seems to be a problem with the TLS certificate
 on your mail server. Are you aware of this?

 Roger