diff --git a/example/callback.php b/example/callback.php
index dca65627e..09b77f093 100644
--- a/example/callback.php
+++ b/example/callback.php
@@ -14,12 +14,13 @@
 $provider = strtolower($_GET['provider']);
 
 switch ($provider) {
+    case 'facebook':
     case 'github':
     case 'vk':
         $provider = $service->getProvider($provider);
         break;
     default:
-        throw new \Exception('Wrong $provider passed in url : ', $provider);
+        throw new \Exception('Wrong $provider passed in url : ' . $provider);
         break;
 }