diff --git a/app/src/main/java/eu/faircode/email/AdapterMessage.java b/app/src/main/java/eu/faircode/email/AdapterMessage.java
index 2b51d63c1e..dc466e63a5 100644
--- a/app/src/main/java/eu/faircode/email/AdapterMessage.java
+++ b/app/src/main/java/eu/faircode/email/AdapterMessage.java
@@ -6460,8 +6460,12 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
                     try {
                         if (ActivityBilling.activatePro(context, uri))
                             ToastEx.makeText(context, R.string.title_pro_valid, Toast.LENGTH_LONG).show();
-                        else
-                            ToastEx.makeText(context, R.string.title_pro_invalid, Toast.LENGTH_LONG).show();
+                        else {
+                            Uri invalid = Uri.parse(BuildConfig.PRO_FEATURES_URI + "invalid.html" +
+                                    "?challenge=" + ActivityBilling.getChallenge(context) +
+                                    "&version=" + BuildConfig.VERSION_CODE);
+                            Helper.view(context, invalid, true);
+                        }
                     } catch (NoSuchAlgorithmException ex) {
                         Log.e(ex);
                         ToastEx.makeText(context, Log.formatThrowable(ex), Toast.LENGTH_LONG).show();
diff --git a/app/src/play/java/eu/faircode/email/ActivityBilling.java b/app/src/play/java/eu/faircode/email/ActivityBilling.java
index 86b1e2d9ec..70200bbef7 100644
--- a/app/src/play/java/eu/faircode/email/ActivityBilling.java
+++ b/app/src/play/java/eu/faircode/email/ActivityBilling.java
@@ -210,7 +210,7 @@ public class ActivityBilling extends ActivityBase implements
                 prefs.getBoolean("test_iab", false));
     }
 
-    private static String getChallenge(Context context) throws NoSuchAlgorithmException {
+    static String getChallenge(Context context) throws NoSuchAlgorithmException {
         String android_id = Settings.Secure.getString(context.getContentResolver(), Settings.Secure.ANDROID_ID);
         if (android_id == null) {
             Log.e("Android ID empty");