Errors configuring roundcube

I have followed the tutos about mail server.

I’m on the part of roundcube and have problems:
the postfixadmin works and i created a user.

errors when testing config roundcube:
Trying to send email…
SMTP send: NOT OK(Authentication failure: STARTTLS failed (Code: ))

and testing connection roundcube
Connecting to ssl://…
IMAP connect: NOT OK(Login failed for [email protected] against from [my IPv6] Could not connect to ssl:// Unknown reason)

The let’s encrypt certs are configure in the /etc/nginx/site-enable/

  • Ports are open in UFW
  • i have the A and AAAA DNS entry OK for w3bmail

have you an idea about the problem?

The hostname of your Postfix and Dovecot server is so you should configure your webmail to connect to SSL://, not SSL://