Changed MX record at GoDaddy according to MS instructions.  Email works, but sent messages are marked as sent from a Hotmail account, on behalf of my email address, and I get the above error message.  Reset the MX record at GoDaddy (although the existing record appeared to be OK).  Same result.  I've noticed that someone from MS has investigated this problem on some accounts and made adjustments.  I'm hoping for the same.  The email address in question is *** Email address is removed for privacy ***.