diff --git a/app/static/js/iframe.js b/app/static/js/iframe.js
index 72332c5..17f96dd 100644
--- a/app/static/js/iframe.js
+++ b/app/static/js/iframe.js
@@ -168,7 +168,12 @@ function observeIframeNavigation() {
   const iframe = mainElement.querySelector("iframe");
   if (!iframe || !iframe.contentWindow) return;
 
-  let lastUrl = iframe.contentWindow.location.href;
+  let lastUrl;
+  try {
+    lastUrl = iframe.contentWindow.location.href;
+  } catch (e) {
+    return;
+  }
 
   setInterval(() => {
     try {