ORA-16600
        Client is not connected to target standby database.
        
        
        Cause
        The SWITCHOVER or FAILOVER command failed because the client was not connected to the target standby database.
        Action
        Explicitly connect to the standby database that is to become the the new primary and retry.
        
     
    
    
        ORA-16600
        not connected to target standby database
        
        
        Cause
        The switchover or failover command failed because the client was not connected to the target standby database of the failover or switchover command.
        Action
        Explicitly connect to the standby database that is to become the the new primary and retry the failover or switchover command.
        
     
    
    
        ORA-16600
        not connected to target standby database for failover
        
        
        Cause
        The failover command failed because the client was not connected to the target standby database.
        Action
        Explicitly connect to the standby database to be failed over to and retry the failover command.