Hi,
Thank you for posting your query.
Kindly follow the steps provided below to resolve your issue.
One thing to note here is that the Cluster action is only if any of the subsystems report an “ error ”, no action is taken on a warning.
So effectively what happens is the following:
Cluster service runs LooksAlive check
Sp_server_diagnostics results sent to Resource Monitor DLL
Resource Monitor DLL detects any error state and notifies the cluster service
Cluster Service takes the resource offline
Notifies SQL Server to issue an internal command to take the availability group offline.
There is also the whole concept of a lease that is explained here
Go to this link for your reference and other troubleshooting procedures https://techcommunity.microsoft.com/t5/core-infrastructure-and-security/sql-2012-alwayson-availability-groups-automatic-failover-a-look/ba-p/370428
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