Fix crash

tournaments/models/tournament.py

@@ -278,6 +278,7 @@ class Tournament(models.Model):
             match_groups.append(self.group_stage_match_group(group_stage, broadcasted, hide_empty_matches=False))
         elif round_id:
             round = self.round_set.filter(id=round_id).first()
+            if round:
                 match_groups = self.round_match_groups(round, broadcasted, hide_empty_matches=False)
         else:
             match_groups = self.all_groups(broadcasted)