Hello Joshua,

I found a page on this error on Microsoft's official site, you can view it here:
http://technet.microsoft.com/en-us/l.../cc957018.aspx

Also, if you can provide the full error with the header information, it may help us troubleshoot.

You can also paste the bounce message into this Parse tool, which can help you read the errors:
http://www.inmotionhosting.com/suppo...ce-back-parser

I hope this helps,
-John-Paul