ORA-16666: unable to initiate fast-start failover on a bystander standby database
Cause:
The request to initiate a fast-start failover using DBMS_DG.INITIATE_FS_FAILOVER was made on a bystander standby database. DBMS_DG.INITIATE_FS_FAILOVER can only be called on either the primary or fast-start failover target standby database.
Action:
Call DBMS_DG.INITIATE_FS_FAILOVER on either the primary or fast-start failover target standby database.