When you set up email forwarding or configure a new MTA, you will want to confirm it is working before relying on it for alerts. A quick test is all you need.
Send a test message
mail -s Test myEmail@gmail.comIf the mail command is not available, install it with apt-get install mailutils. Then check your inbox.
If it does not arrive
Run mailq to see if the message is stuck in the queue. The mail log at /var/log/mail.log will also show the delivery attempt and any errors.
Enjoy!