diff --git a/src/drivers/webextension/js/lib/iframe.js b/src/drivers/webextension/js/lib/iframe.js
index 01c9cf304..8a1b322fe 100644
--- a/src/drivers/webextension/js/lib/iframe.js
+++ b/src/drivers/webextension/js/lib/iframe.js
@@ -997,6 +997,8 @@
         return;
       }
 
+      if (!adData) return;
+      
       if (adData.postMessageId === POST_MSG_ID) {
         delete adData.postMessageId;