Availability replica is disconnected
This policy checks the connection state between availability replicas. The policy is in an unhealthy state when the connection state of the availability replica is DISCONNECTED. The policy is otherwise in a healthy state.
For this release of SQL Server 2014, information about possible causes and solutions is located at Availability replica is disconnected on the TechNet Wiki.
The secondary replica is not connected to the primary replica. The connected state is DISCONNECTED. This issue can be caused by the following:
The connection port might be in conflict with another application.
The encryption type or algorithm is mismatched.
The connection endpoint has been deleted or has not been started.
The transport is disconnected.