The local node is not part of quorum

I set up Availability Group in SQL Server. However, after reboot both servers, the primary and the second, I ran into this error:

 “The local node is not part of quorum and is therefore unable to process this operation”

Solution

1. Go back to SQL Server Configuration Manager and unticked “Enable AlwaysOn Availability Groups” on both servers,
2. Reboot and then retick the “Enable AlwaysOn Availability Groups”
3. Reboot both servers

Though I had done this in the very beginning, I had to do this again to resolve the issue. If you encounter the same issue, do this setting again.