We are in the process of migrating from Exchange 2003 to 2010. The 2010 box has been up and running properly for a few weeks with several mailboxes. After a server reboot of the 2010 box I can now no longer send internal emails from the 2010 to 2003. All external emailsfrom the 2010 are being sent and recieved without any issues. 2003 users can also successfully send to the 2010 users.
I have read through some of the other posts but so far I am not having any success and am stuck. I would appreciate any suggestions.