When adding a new client to the Plesk interface, as it goes from their information to the loading of the IP pool page, the error "Unable to send notification: mail() failed:" is broadcasted. I have to click OK to move on. Also, when users add their domains they get some similar errors. Any idea how to fix this? As far as I know, the entire Plesk package is setup like it ought ot be. I can't find any mistaken options/information anywhere. Thanks a lot.