diff --git a/src/Tiny_httpd_server.ml b/src/Tiny_httpd_server.ml
index 30c35d11..9378faae 100644
--- a/src/Tiny_httpd_server.ml
+++ b/src/Tiny_httpd_server.ml
@@ -40,6 +40,7 @@ module Response_code = struct
     | 302 -> "Found"
     | 304 -> "Not Modified"
     | 400 -> "Bad request"
+    | 401 -> "Unauthorized"
     | 403 -> "Forbidden"
     | 404 -> "Not found"
     | 405 -> "Method not allowed"