Ok, here's my problem. I installed PHP-Nuke on my server and I also had this problem with InvisionBoards Anyways here it is...
The users dosn't get their confermation e-mail. And I cannot snet out newsletters. Also When I try to sned out mass-mail to all my users in InvisionBoards I get this problem also.

Quote from FeedBack on PHP-NUKE
Warning: Failed to connect to mailserver, verify your "SMTP" setting in php.ini in c:\apache\htdocs\unerror\html\modules\Feedback\index.php on line 79

Mail has been sent!

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I donno what do to. :|