The log for database ‘xxxxx’ cannot be shrunk until all secondaries have moved past the point where the log was added.
Problem with Always On. One of the secondary was not getting synchronized. Delete the AG and the thing came back to normal.
But in production, if you can’t afford to delete and reconfigure Always On availability group, then you need to find the cause why secondary is not getting synchronized with primary. In theory, the transaction log files on primary would keep on growing due to secondary not synchronizing with primary. If you find that the data movement is suspended, then you may want to resume it and find the possible cause in the SQL Server ERRORLOG file
One of the possible case I can think of is a change of the service account.