diff -urNp gnome-shell-3.20.3.orig/js/portalHelper/main.js gnome-shell-3.20.3/js/portalHelper/main.js
--- gnome-shell-3.20.3.orig/js/portalHelper/main.js	2016-08-13 11:03:23.378917513 +0200
+++ gnome-shell-3.20.3/js/portalHelper/main.js	2016-08-13 11:21:04.858275910 +0200
@@ -64,6 +64,16 @@ const PortalWindow = new Lang.Class({
 
         this._webView = new WebKit.WebView();
         this._webView.connect('decide-policy', Lang.bind(this, this._onDecidePolicy));
+        this._webView.connect('load-changed', Lang.bind(this,
+            function(webView, loadEvent) {
+                let uri = webView.get_uri();
+                log('*** DEBUG: load-changed: ' + uri + ', ' + loadEvent);
+            }));
+        this._webView.connect('load-failed-with-tls-errors', Lang.bind(this,
+            function(webView, failingUri, certificate, errors) {
+                let uri = webView.get_uri();
+                log('*** DEBUG: load-failed-with-tls-errors: ' + uri);
+            }));
         this._webView.load_uri(url);
         this._webView.connect('notify::title', Lang.bind(this, this._syncTitle));
         this._syncTitle();
