Reverse DNS does not match SMTP Banner

[thepra]

From mxtoolbox.com at the SMTP Banner Check I get a warning which says: Reverse DNS does not match SMTP Banner
But looking around the web I didn't get what's it about and how should I fix it, does anyone have any idea of what's going on?

[foxcpp]

A SMTP server sends its hostname as part of the banner message. For maddy it is defined via hostname directive ($(hostname) = example.org).

Your servers IP address should have a PTR record containing that hostname (look for Reverse DNS in your providers control panel). It should also resolve correctly back to the same IP address.