Zkus:

1.) Goto your Exchange administrator MMC.
2.) Under your administrative group and %YourServerName% open the Protocols folder and under SMTP, goto the properties of your Default SMTP Virtual server.
3.) Click on "Delievery" tab and then the "Advanced" button.
4.) under Fully-qualified domain name. Put in... "%YourServerName%.company.com"
5.) Press OK and test.