ORA-16911
Redo data from new source database has not been registered.
Cause
Redo data from the new source database was not registered for this standby pluggable database.
Action
Ensure the previous role change command completed successfully. If there were any errors, address the issues and complete the role change. If this still does not address the issues, try restarting recovery. Use the EDIT PLUGGABLE DATABASE SET STATE=APPLY-ON to start Redo Apply and switch logs at the source database.