Assume that you deploy a mix of servers that run Microsoft Exchange Server 2016, 2013, and 2010. You run the following cmdlet in the Exchange Server 2010 Management Shell (EMS) to remove this server as a proxy endpoint:
Set-ClientAccessServer -Identity <server_name> -IsOutofService $True
Note You can restart the MSExchangeADTopology service and the Internet Information Services (IIS) application pools in Exchange Server 2016 to make sure the change takes effect immediately. To determine whether this change has taken effect, try to access a mailbox that's hosted on Exchange Server 2010 by logging on to OWA. If the logon attempt is unsuccessful, this means that the change has taken effect.
Then, you revert the IsOutofService value to False by running the following cmdlet on the Exchange Server 2010 Client Access server (CAS):
Set-ClientAccessServer -Identity <server_name> -IsOutofService $False
In this case, you expect to log on to your mailbox from OWA without any problem. However, you cannot log on to OWA. Additionally, if you try to log on to OWA from the Exchange Server 2016 environment for a mailbox that exists on Exchange Server 2010, the attempts may continue to be unsuccessful for a day or more.