|OS type and version
||Ubuntu Linux 20.04.6
||All installed packages are up to date
Getting this error
: auth failure: [user=] [service=smtp]
Smtp is a mail service not a web service. You do better to look at the apache logs to see what is going wrong with the webserver.
What does the following command return:
sudo systemctl --no-pager status apache2
Try to disable SASL services, everything seem work well after did that.
smtp (pop3, imap maybe as well) authentication will fail if you do that. What is working well?