diff --git a/devtools/shared/webconsole/network-monitor.js b/devtools/shared/webconsole/network-monitor.js
index 25e188cf75..8e61f4fc7c 100644
--- a/devtools/shared/webconsole/network-monitor.js
+++ b/devtools/shared/webconsole/network-monitor.js
@@ -310,9 +310,9 @@ NetworkResponseListener.prototype = {
     }
     try {
       let impl = this._wrappedNotificationCallbacks.getInterface(iid);
-      if(impl) impl[method].apply(impl, args);
+      impl[method].apply(impl, args);
     } catch (e) {
-      if (e.result != Cr.NS_ERROR_NO_INTERFACE) {
+      if (e.name != "TypeError" && e.result != Cr.NS_ERROR_NO_INTERFACE) {
         throw e;
       }
     }