diff --git a/lib/SimpleSAML/Error/AuthSource.php b/lib/SimpleSAML/Error/AuthSource.php
index 4b29f3e555c210d769361396e8c21de799b741f9..3f53115eca3b9d7a8f6ce88b9cfecf312d127dcf 100644
--- a/lib/SimpleSAML/Error/AuthSource.php
+++ b/lib/SimpleSAML/Error/AuthSource.php
@@ -30,7 +30,7 @@ class AuthSource extends Error
      *
      * @param string $authsource  Authsource module name from where this error was thrown.
      * @param string $reason  Description of the error.
-     * @param Exception|null $cause
+     * @param \Exception|null $cause
      */
     public function __construct($authsource, $reason, $cause = null)
     {