I am using Windows 7 and Windows Live Mail.  I have one friend who recently had his work address changed to a "mail.mil" address.  Each time I include his email address in an email, I get an error "The message could not be sent.  Some of the recipients for this message are not valid.  Please verify the names"  I have deleted and reentered the email address several times with no change.  When using Outlook from my "My MSN" page, the address works fine.  Any ideas how to fix this on Windows Live Mail?