The MTU with TLS enabled is exim4 which I am using.
Auth method is plain user name and password with TLS enabled.
My app.yml setup is
When test logging and sending email from localhost, remote address or inside docker container using openssl command, the mail could be sent successfully.
But when I login into admin panel and try to send test mail or invite mail to my friends, the mail logs shows
503 AUTH command used when not advertised
As we know,
EHLO (not HELO) must be given by client before AUTH
When using HELO,
the mail server shows
503 AUTH command used when not advertised ,
So if discourse use HELO by default to connect mail server,
if this is could not be change,
the email could not get authorization and be sent successfully by exim4 wiht TLS.
Is this one of the reasons we could not configure email settings successfully?
Or if you can add
EHLO option to connecting mail server?