I am using
aerc 0.2.1. When I try to send message over SMTP with STARTTLS, I get following error:
conn.Auth: 504 5.7.4 Unrecognized authentication type
My account config has smtp-starttls = yes and outgoing = smtp+plain://...... options. I tried with outgoing = smtp://......, but got same result.
I tried another account that uses
smtp.office365.com server with SMTP/STARTTLS setting, the result is the same 504 error.
I dig more into the problem. smtp.office365.com and some Outlook Exchange SMTP servers only accept LOGIN authentication method which is not implemented yet.