Oracle Solution for Error ora-23312

ORA-23312: not the masterdef according to string

What triggered the Error:

The group name is null, the group name is misspelled, the invocation or given database is not the masterdef, or one of the masters does not believe the invocation database is the masterdef.

What should we do to fix it:

the given group name and masterdef were both correct, connect to the masterdef and retry the request, or relocate the masterdef at the (errant) databases using relocate_masterdef.