If you recently upgraded your Postfix mail server and found your outbound mail being refused as if it wasn’t even trying to authenticate, that actually may be the exact problem.
Postfix 2.10 introduced the new setting of
smtpd_relay_restrictions which can result in authenticated relay being disabled until you add a value to the new setting.
If you want different settings in your main config and your submission settings, make sure you edit both
/etc/postfix/master.cf and reload the service to apply the changes.