ORA-16676: RedoRoutes property for two or more databases contains a circular route
Cause:
The value of a RedoRoutes property for two or more databases was set such that a database that sends redo also receives redo data data in the same route. For example, A sends to B, B sends to C, and C sends to A.
Action:
Correct the setting of the RedoRoutes propety on one or more databases to eliminate the circular route.