During a DR activation the Activation went fine. But when trying to restore the main site after the DR tests are complete were getting the below error

Below was the Current state in the DR site before the restoration to main site :

Version of Exchange – Exchange 2016 CU3 with no coexistence

1) Main site was in stopped state for DAG and All main site exchange
servers were in Stopped mailbox servers list.
2) DR site was activated for DAG and only DR site exchange servers were in started mailbox servers and operational servers list.
3) All the DR copies were mounted , and users were connected.

After the DR tests were completed and trying to start the main site with below command was getting the below error :

Start-DatabaseAvailabilityGroup -ActiveDirectorySite  “MainSite”

A server-side database availability group administrative operation failed. Error The operation failed. CreateCluster errors may result from incorrectly configured static addresses. Error: An error occurred while attempting a cluster operation. Error: Cluster API ‘”AddClusterNode() (MaxPercentage=12) failed with 0x35. Error: The network path was not found”‘

Had a look at the DAG tasks logs and was getting the same above message :

Error: A server-side database availability group administrative operation failed. Error The operation failed. Create Cluster errors may result from incorrectly configured static addresses. Error: An error occurred while attempting a cluster operation. Error: Cluster API failed: “AddClusterNode() (MaxPercentage=12) failed with 0x35. Error: The network path was not found”.

Additionally was getting this message in the DAG Task logs

WriteError! Exception = Microsoft.Exchange.Management.Tasks.FailedToStartNodeException: Start-DatabaseAvailabilityGroup failed to start server

Solution :

Followed the below blog steps and it worked :

https://amagsmb.wordpress.com/2015/09/16/problem-adding-a-second-server-to-dag-error-cluster-api-addclusternode-maxpercentage12/

The Remote Registry Service should have the Startup type set to Automatic and be started.
An SP, Windows update or RU installation will put the service in a disabled state and it might be in that state after the update. In my case the main site servers OS were patched last week and post the patches these services might have gone to disabled state. While stopping  and evicting these nodes on activating the DR site there were no issues this was strange and went smooth without any issues.

The real issue happened  only when we tried to activate the main site on re adding these servers back to the DAG group.

Reason:

Some Exchange EMS/Power Shell functions, such as managing diagnostics logging requires the remote registry service to be enabled. So the Exchange required this service on the  remote servers to add them on the node. If this service is not started then the servers will not join in the DAG.

Thanks & Regards
Sathish Veerapandian