diff --git a/specification/10_client_server_api.rst b/specification/10_client_server_api.rst
index 17eca502..8d9f651b 100644
--- a/specification/10_client_server_api.rst
+++ b/specification/10_client_server_api.rst
@@ -131,9 +131,7 @@ If the home server decides the attempt was unsuccessful, it returns an error
 message in the standard format::
 
   {
-    "errcode": [
-        "M_EXAMPLE_ERROR"
-    ],
+    "errcode": "M_EXAMPLE_ERROR",
     "error": "Something was wrong"
   }