diff --git a/roles/custom/matrix-authentication-service/defaults/main.yml b/roles/custom/matrix-authentication-service/defaults/main.yml
index 233dd5676..c86ba0cc9 100644
--- a/roles/custom/matrix-authentication-service/defaults/main.yml
+++ b/roles/custom/matrix-authentication-service/defaults/main.yml
@@ -327,7 +327,7 @@ matrix_authentication_service_config_http_listener_web_resources_default: |-
       {'name': 'assets'},
     ]
     +
-    [{'name': 'adminapi'} if matrix_authentication_service_admin_api_enabled else []]
+    ([{'name': 'adminapi'}] if matrix_authentication_service_admin_api_enabled else [])
   }}
 matrix_authentication_service_config_http_listener_web_resources_auto: []
 matrix_authentication_service_config_http_listener_web_resources_custom: []