I have two Exchange servers in my organization. Server1 is the original and Server2 is the new server to which I want to migrate all of my users so that I can upgrade the original server to 2007. I tested successfully three accounts before this last one, and they all worked fine over IMAP, SMTP, Webmail and Exchange protocols. The last user I moved could not send over the new SMTP server. With a telnet to either the secure or standard port of it, he would get an error that he did not have permissions to send mail from his own account. He was able to send via webmail and he was able to receive over IMAP. I checked his mailbox rights, which were the same as anyone else’s, and the server is set to allow any authenticated user as well as Basic authentication over TLS. The only difference between this and Server1’s SMTP server is that anonymous logins are no longer allowed. As I said though I was able to get three other more or less identical accounts to work. I figured a way for him to be able to send over the SMTP server by adding him to the group Domain Admins, but this is only a workaround and I want to avoid this if I can, especially if it happens to any of my other users. Does anyone have any suggestions?