diff --git a/cmd/qfs/main.go b/cmd/qfs/main.go
index 8d3a490..d8602b6 100644
--- a/cmd/qfs/main.go
+++ b/cmd/qfs/main.go
@@ -1544,7 +1544,8 @@ func setupRouter(cfg *config.Config, local *localdb.LocalDB, connMgr *db.Connect
 				project, err := projectService.Update(c.Param("uuid"), dbUsername, &req)
 				if err != nil {
 					switch {
-					case errors.Is(err, services.ErrReservedMainVariant):
+					case errors.Is(err, services.ErrReservedMainVariant),
+						errors.Is(err, services.ErrCannotRenameMainVariant):
 						respondError(c, http.StatusBadRequest, "invalid request", err)
 					case errors.Is(err, services.ErrProjectCodeExists):
 						respondError(c, http.StatusConflict, "conflict detected", err)