diff --git a/Provider.php b/Provider.php
index ab9aee9..ab2d3d3 100755
--- a/Provider.php
+++ b/Provider.php
@@ -32,7 +32,7 @@ class Provider extends AbstractProvider
     protected function getAuthUrl($state)
     {
         return $this->buildAuthUrlFromBase(
-            'https://login.microsoftonline.com/'.($this->config['tenant'] ?: 'common').'/oauth2/authorize',
+            'https://login.microsoftonline.com/'.($this->config['tenant'] ?? 'common').'/oauth2/authorize',
             $state
         );
     }