RegisterMatchmakerOverride not work,and the Matchmaker did not work

when only RegisterMatchmakerMatched,it worked.
but when I add RegisterMatchmakerOverride.it not work.

	if err := initializer.RegisterMatchmakerOverride(logic.MatchmakerFilter); err != nil {
		logger.Error("Unable to register: %v", err)
		return err
	}



func MatchmakerFilter(ctx context.Context, logger runtime.Logger, db *sql.DB, nk runtime.NakamaModule, candidateMatches [][]runtime.MatchmakerEntry) (matches [][]runtime.MatchmakerEntry) {
	logger.Info("enter MatchmakerFilter", len(candidateMatches))
	return candidateMatches
}

@sesposito need help.thanks