diff --git a/src/Auth/ServiceClient.php b/src/Auth/ServiceClient.php
index c04c4826..fabbb3c6 100644
--- a/src/Auth/ServiceClient.php
+++ b/src/Auth/ServiceClient.php
@@ -1,4 +1,4 @@
-php
+<?php
 
 namespace Microsoft\BingAds\Auth;