diff --git a/addons/web/static/src/legacy/js/public/public_root.js b/addons/web/static/src/legacy/js/public/public_root.js
index 86793f50a8c54..73635d0427fb9 100644
--- a/addons/web/static/src/legacy/js/public/public_root.js
+++ b/addons/web/static/src/legacy/js/public/public_root.js
@@ -246,7 +246,9 @@ export const PublicRoot = publicWidget.RootWidget.extend({
         this._startWidgets(ev.data.$target, ev.data.options)
             .then(ev.data.onSuccess)
             .catch((e) => {
-                ev.data.onFailure(e);
+                if (ev.data.onFailure) {
+                    ev.data.onFailure(e);
+                }
                 if (!(e instanceof RPCError)) {
                     return Promise.reject(e);
                 }