DCOM was unable to communicate with the computer “server_name.domain_name” using any of the configured protocols; requested by PID

ERROR:

DCOM was unable to communicate with the computer “server_name.domain_name” using any of the configured protocols; requested by PID     5cac (C:\Windows\system32\ServerManager.exe).

Event Id in the Windows System Event Log: 10028.

EXPLANATION:

We started to encounter this error after removing 3 nodes from an environment with AlwaysOn Availability Groups. The number of nodes was the maximum number allowed by SQL Server 2012.

Friends from the system unit noticed this error. Of course I started to examine the problem with the error message. The most striking thing in the error message was “ServerManager.exe” at the end of the message. So the problem was somehow related to the Server Manager tool. When I opened Server Manager, I saw the name of the 3 nodes we removed from AlwaysOn and Cluster in the “All Servers” section. Although I remove these nodes from AlwaysOn and Cluster, I think they remain in Server Manager. I don’t know why yet.

SOLUTION:

To solve the problem, I simply removed two of these servers from the All Servers section in Server Manager with the “Remove Server” option. But the system did not allow me to remove the third. Actually it was asking me if I’d like to remove the selected node and all the other nodes from the Cluster. It’s a scary message, isn’t it? Of course I canceled the process.

After closing Server Managers in all open sessions in the third node, I was able to remove it.