Fix an-always-on secondary replica goes into a disconnecting state

SQL SERVER – Always On Replica Disconnected SQL AlwaysOn Availability Group Secondary Replica Disconnects Immediately After Setup. While setting up a SQL AlwaysOn Availability Group I ran into a very interesting problem. I had created the AG while preparing for an upcoming speaking engagement so I’d setup two VMs (Node A and Node B) and checkpointed them immediately before creating the AG. This way I could just go back to the checkpoint and start the demo during my presentation. This turned out to be very helpful because for the very first time I ran into an issue setting up a SQL AlwaysOn Availability Group. All previous configurations had gone flawlessly. After a lot of head scratching and reverting the VMs to try again; the only error I could get from the AG Dashboard is: “This secondary replica is not connected to the primary replica. The connected state is DISCONNECTED.” Node B would simply NOT connect to the AG.