diff --git a/src/XML/fed/AbstractSecurityTokenServiceType.php b/src/XML/fed/AbstractSecurityTokenServiceType.php
index 1c5702af..5164db9f 100644
--- a/src/XML/fed/AbstractSecurityTokenServiceType.php
+++ b/src/XML/fed/AbstractSecurityTokenServiceType.php
@@ -77,7 +77,7 @@ final public function __construct(
         Assert::minCount($securityTokenServiceEndpoint, 1, MissingElementException::class);
         Assert::allIsInstanceOf(
             $securityTokenServiceEndpoint,
-            AbstractSecurityTokenServiceType::class,
+            AbstractSecurityTokenServiceEndpoint::class,
             SchemaViolationException::class,
         );
         Assert::allIsInstanceOf(