Dear Exchange administrators, It is something that I can not figure why as this issue is only affecting ONE mail domain only from Exchange 5.5 with SP4 installed.. EXCEPT to ONE mail domain only, all other mail domains are going out fine. However the users are able send their mails to this mail domain through HOTMAIL. I would appreciate to hear any hints, thank you. BY THIS E-MAIL IS CONFIDENTIAL. If you have received this e-mail in error, please notify us by return e-mail and delete the document. If you are not the intended recipient you are hereby notified that any disclosure, copying, distribution or taking any action in reliance on the contents of this information is strictly prohibited and may be unlawful. Bayside Health is not liable for the proper and complete transmission of the information contained in this communication or for any delay in its receipt.