Exchange 2010 Client Access Server Version does not match accessed resources Mailbox Server Version

Question

I have recently installed an exchange 2010 machine along side an Exchange 2007 machine. Everything is working except external EWS for mailboxes that I have moved to the 2010 machine mailbox database.

When I run Microsoft Exchange Web Services Connectivity Tests on https://www.testexchangeconnectivity.com for a mailbox that is on the Exchange2010 server, I get the message: The Client Access Server version does not match the accessed resource's Mailbox Server version.

I can however access the mailbox internally, by using the local exchange server 2010 address.

If I run the same test for a mailbox on the 2007 server it works.

I am not sure what to do to fix this. My autodiscover URL points to the Exchange 2010 machine.

Answer 1

I found out that this was being caused by the NAT. It was still set up to only go to the old exchange server. Once allowing port 443 and 25 to go to the new server it was all working.