There is no replica for that mailbox on this server with IMAP

Now that Apple will support Microsoft push/pull technology, we have made the decision to try the iPhone.  Problem is that since the new iPhone 2.0 software won’t be out until June, I had to get IMAP working on our Exchange server to keep us going. 

Problem:  At times, I get the error “There is no replica for that mailbox on this server” when trying to access my Exchange server through IMAP on my iPhone.  I don’t always get it but sometimes I do and it’s annoying. 

Solution:  It looks like that if you have a wireless access point and if your iPhone is attached to it, it will use that connection first to download the mail. That makes sense because it’s usually a faster connection than then AT&T network.  The problem with using the AP in our network was that I didn’t have a rule in our firewall to re-route the IMAP request.  Once I did that, my email synced fine and didn’t get the error again. 

Problem #2:  When I am on the AT&T network, the iPhone seems to get stuck when trying to sync.  I connects to the server and sees how many emails needs to be downloaded but it just sits there saying “downloading 1 of x amount of emails.”  At this point, I don’t know if this is an iPhone/AT&T network issue or a server issue.  I am more inclined to think that it’s not the server because I’m able to connect through other IMAP clients just fine. 

Solution #2:  None yet, I’m asking anyone who reads this, if you have an idea or something that might help, leave a comment. I would greatly appreciate it.