Oracle Solution for Error ora-23500

ORA-23500: cannot switch master for a multi-tier materialized view repgroup "string"."string"

What triggered the Error:

attempt was made to switch master for a materialized view repgroup when its parent repgroup is also a materialized view repgroup. This is not allowed.

What should we do to fix it:

op and recreate the materialized view repgroup based on a proper parent repgroup.