[TYPO3] Problem with mailform

[Redvald Hjulstad]

Hi list

I have insertet a mailform on a page. When Submiting i get the following 
error:

Warning: mail() [function.mail]: SMTP server response: 550 Requested 
action not taken: mailbox unavailable or not local in 
E:\inetpub\vhosts\ceteq.com\httpdocs\t3lib\class.t3lib_htmlmail.php on 
line 712

Warning: Cannot modify header information - headers already sent by 
(output started at 
E:\inetpub\vhosts\ceteq.com\httpdocs\t3lib\class.t3lib_htmlmail.php:712) 
in 
E:\inetpub\vhosts\ceteq.com\httpdocs\typo3\sysext\cms\tslib\class.tslib_fe.php 
on line 2853




I have tried to send mail from the configuration part of Typo3, and that 
is working.


Any suggestions?
Typo3 4.0.7



Redvald