I Finally got my web server to run as per this tutorial and i am so close. I get these errors.
/var/log/mail.log
</>
Jun 19 13:29:55 mail postfix/submission/smtpd[1797]: fatal: in parameter smtpd__relay_restrictions or smtpd_recipient_restrictions, specify at least one working instance of: reject_unauth_destination, defer_unauth_destination, reject, defer, defer_if_permit or check_relay_domains
</>
nextcloud log
</>
could not send message: Error when communicating with the server.
</>