diff --git a/cmd/backoffice/fileserver.go b/cmd/backoffice/fileserver.go
index 0480f8a..ad7602d 100644
--- a/cmd/backoffice/fileserver.go
+++ b/cmd/backoffice/fileserver.go
@@ -147,6 +147,7 @@ func (fs *FileServer) CartHandler(w http.ResponseWriter, r *http.Request) {
 	id, ok := isValidId(idStr)
 	if !ok {
 		writeJSON(w, http.StatusBadRequest, JsonError{Error: "invalid id"})
+		return
 	}
 	// reconstruct state from event log if present
 	grain := cart.NewCartGrain(id, time.Now())