550 5.7.1 This message does not comply with required standards
 

I have been getting the following error messages when trying to respond to some emails using Outlook 2003 The following recipient(s) could not be reached: John Doe's gmail on 8/12/2010 1:51 PM You do not have permission to send to this recipient. For assistance, contact...

This post is*very*informative.*Thank you!