While creating a new Exchange 2016 DAG for a client, the servers kept bombing out with a WMI exception “RPC Server is unavailable” error. After scouring the net everything pointed towards blocked RPC ports 6001-6032. For us, this simply was not the case.
After investigating a little further I realized that there was an issue with Windows Failover Clustering not installing properly during the DAG creation process. I decided to check the servers and sure enough, they were pending a restart. I’m not sure if this is an issue with Exchange 2016, DAG’s in general, or the clients environment. I’ve never ran into this issue before so it upended me just a bit. I figured I’d give it a good old reboot. Sure enough, the installation was able to complete.
I don’t have any screenshots or I would include them to help if anyone runs into this issue and wants to compare. If you’re out of ideas or it’s not a firewall issue, check Windows Failover Clustering installation on your Exchange DAG Servers. It might save you time and a headache!