Symptom
Cannot send mail:
There could be numerous reasons for not being able to send mail. The most common reasons are
- The SMTP server has the wrong port,
- The SMTP server credentials (username/password) are wrong,
- The SMTP server is not permitted to send on your domain,
- Sender address is rejected: The SMTP user <mail@yourdomain.net> is not authenticated to send from domain <Site mail address>.