Problem sending mail

[erilar]

I have a strange problem. When I send mail to [email protected] I get the following error msg: "There was an error sending your message: Failed to add recipient: [email protected] [SMTP: Invalid response code received from server (code: 550, response: sorry, no mailbox here by that name. (#5.7.17))]"

If I instead send to user@www.domain.com everything works just fine.
Is there any way to fix this?
Running plesk on Suse 10.0.

 

[poke]

most likely in your dns zone you have:
A Record www.domain.com - mail.domain.com

it needs to be

A Record domain.com - mail.domain.com

I might be wrong, I'm just assuming

 

[erilar]

The mail server is hosted on a different network.

I have set up my dns zone with mx and a record pointing to the right place.

Thanks for trying to help