diff --git a/testing/web-platform/meta/service-workers/cache-storage/window/sandboxed-iframes.https.html.ini b/testing/web-platform/meta/service-workers/cache-storage/window/sandboxed-iframes.https.html.ini
index 0e0496e706c5..88fa29ce3bac 100644
--- a/testing/web-platform/meta/service-workers/cache-storage/window/sandboxed-iframes.https.html.ini
+++ b/testing/web-platform/meta/service-workers/cache-storage/window/sandboxed-iframes.https.html.ini
@@ -1,3 +1,5 @@
 [sandboxed-iframes.https.html]
   type: testharness
   prefs: [dom.caches.enabled:true]
+  [Sandboxed iframe without allow-same-origin is denied access]
+    expected: FAIL