Message Oracle RMAN-20079 - full resync from primary database is not done

ERRORfull resync from primary database is not done
CAUSEResync from standby detected that a full resync from primary database is required. One of the following events on primary database may have caused this error: 1) one or more tablespaces or datafiles were added 2) one or more tablespaces or datafiles were dropped 3) one or more datafiles status changed
ACTIONPerform full resync after connecting to primary database.