diff --git a/api/pkg/s3/service.go b/api/pkg/s3/service.go
index e538c48ed..9cc22b7f3 100644
--- a/api/pkg/s3/service.go
+++ b/api/pkg/s3/service.go
@@ -180,6 +180,10 @@ func (s *APIService) GetBackendIdFromTier(ctx context.Context, tierName string)
 		response.WriteError(http.StatusInternalServerError, err)
 		return ""
 	}
+
+	if len(res.Tiers[0].Backends) == 0 {
+		return ""
+	}
 	backendId = res.Tiers[0].Backends[rand.Intn(len(res.Tiers[0].Backends))]
 
 	return backendId
diff --git a/backend/pkg/db/drivers/mongo/mongo.go b/backend/pkg/db/drivers/mongo/mongo.go
index cc4ceb194..b171cfcdf 100644
--- a/backend/pkg/db/drivers/mongo/mongo.go
+++ b/backend/pkg/db/drivers/mongo/mongo.go
@@ -235,7 +235,7 @@ func (repo *mongoRepository) UpdateTier(ctx context.Context, tier *model.Tier) (
 	if err != nil {
 		return nil, err
 	}
-	_, err = session.Database(defaultDBName).Collection(defaultTierCollection).UpdateOne(ctx, m, tier)
+	_, err = session.Database(defaultDBName).Collection(defaultTierCollection).UpdateOne(ctx, m, bson.M{"$set": tier})
 	if err != nil {
 		return nil, err
 	}
@@ -257,7 +257,7 @@ func (repo *mongoRepository) ListTiers(ctx context.Context, limit, offset int, q
 	}
 	log.Infof("ListTiers, limit=%d, offset=%d, m=%+v\n", limit, offset, m)
 
-	cur, err := session.Database(defaultDBName).Collection(defaultCollection).Find(ctx, m)
+	cur, err := session.Database(defaultDBName).Collection(defaultTierCollection).Find(ctx, m)
 
 	if err != nil {
 		return nil, err