diff --git a/docker/simplesamlphp/sp/config/authsources.php b/docker/simplesamlphp/sp/config/authsources.php
index 610f87d..e310e15 100644
--- a/docker/simplesamlphp/sp/config/authsources.php
+++ b/docker/simplesamlphp/sp/config/authsources.php
@@ -75,6 +75,9 @@
             'urn:oid:x.x.x.x',
         ],
         */
+
+        // IDP message security error on singlelogout without this
+        'sign.logout' => true,
     ],