We’ll be using telnet to connect to a mail server and send ourselves an email.
The parts in bold are the commands to enter.
[bob@linux ~]$ telnet mail.website.com 25
Connected to mail.website.com.
Escape character is '^]'.
220-mail.website.com ESMTP Exim 4.85 #2 Mon, 09 May 2022 22:12:59
220-We do not authorize the use of this system to transport unsolicited,
220 and/or bulk e-mail.
250 mail.website.com Hello domainto.sendfrom.com [192.168.1.2]
MAIL FROM: <firstname.lastname@example.org>
RCPT TO: <email@example.com>
354 Enter message, ending with "." on a line by itself
Subject: Test MessageThis is a test.
250 OK id=5a1g7i-1347MT-1p
221 mail.website.com closing connection
Connection closed by foreign host.
The first two “2, and 2,ab” mean that the message has not been read. The bottom 2 “2,S and s,Sab” mean that the message has been read or “seen?”. Guess that is what the S is for. Not sure what ab is for.
The certificate does not match the expected identity of the site that it was retrieved from.
The server's identity does not match the identity in the certificate
Hostname in certificate didn't match
The reason for the above errors are due to the fact that the email client is trying to use mail.mydomain.com and the email server is mail.emailserver.com.
So the email client pulls the certificate for mail.emailserver.com and reads that this certificate is for mail.emailserver.com, NOT for mail.mydomain.com. Hence the conflict and it throws an error.
If you can, accepting the certificate should let everything work. It appears that on recent versions of iOS their may be some problems trusting it. The other work around is to use the actual mail server host. So mail.emailserver.com