Dear All, In order to transition process of exchange server 2003 to 2007 I have successfully transitted my exchange server 2003 SP2 to exchange server 2007 SP3 on Windows Server 2008 R2 SP1. I am having a single forest with a single DC. This DC machine was running on Windows Server 2003, X86 Enterprise Edition SP2 R2 Now, In order to move this DC into Windows server 2008 X64 Operating system. I have to first make Windows Server 2003, X64 DC. because I can not directly move my existing Server 2003 32 bit DC into Server 2008 64 bit DC. To doing so, I have configured one Windows Server 2003, X64 Standard Edition SP2 as an Additional DC of my primary DC. After doing so, I have transfer GC, FSMO with my X64 OS machine. After doing so, I have restarted everyting. After doing so, I have found, there is a problem with exchage server. I cannot send an outbound mail from my organization. but, I can receive an email from internet. After that, I have removed my existing Edge subscription. and make a new subscription from Edge server and configured it with EMC. but still, there is a same problem. I cannot send outbound mail. but I can receive an internet mails. After all, I wanted to my all servers should works on Windows Server 2008 X64 edition. Please give a solution. Bhavyang R Patwari https://www.mcpvirtualbusinesscard.com/vbcserver/bhavyangraj/profile