I have Exch 2003 sp2, today messages sent to my server are getting bounced back with a message user@xxxxxxx You do not have permission to send to this recipient, for assistance contact your admin. <XXXXX.org # 5.7.1 smtp;550 5.7.1 65.xxx.xxx.xxx has been blocked by grandhyattbali.com> I am not have any connection with grandhyattbali.com we are a small local hospital. Any Ideas?