If you are trying to setup System Centre Data Protection Manager 2010 with a SMTP relay that dosn’t use authentication (e.g. you use IP address filtering to allow access to your SMTP server) you may come across a problem where DPM throws up a error every time you try and send a email stating that a username/password must be entered.
The full error message is:
Details: Logon failure: unkown username or bad password
Simple solution to this problem is to put in a username/password for a user account that has admin privileges on the DPM server.
Once that is in DPM will send emails off to any address you like quite happily.