It is also my understanding that even if the 2016 Clients connect to the 2016 Exchange Server, that it should proxy them back to the 2010 Server. But the 2016 clients are still attempting to connect to it. And as a last resort attempted to turn the server off. What do I need to do to get the Outlook 2016 clients to stop trying to connect to this 2016 Exchange Server that has not yet been setup? I have set the AutoDiscoverServiceInternalURI on the 2016 server to $null. All of this seemed to work in my test environment. On the 2016 server I have configured the virtual directories to point to the 2010 server.

I realize that this is caused by too many RPC failures.

This goes on for about 5 minutes and then they automatically connect to the correct 2010 server. They fail to connect and go into disconnected status. My Outlook 2016 clients have intermittently started trying to connect to it and more specifically seem to be failing to connect to the 'Exchange Directory' service. The problem that I am having is that once I spun up my 2016 exchange server. We do not use Outlook anywhere, and the Autodiscover is pointed at the 2010 exchange server's CASArray. My client computers are running Outlook 3/16 I have an Exchange 2010 environment that I am planning on upgrading to exchange 2016 and will be configuring for co-existence so that I may perform the upgrade in steps over time.

How to upgrade to outlook 2016