From dd79c096be281fb377cd97e5f47d5d3c08b7f5ac Mon Sep 17 00:00:00 2001
From: saqimtiaz <saq.imtiaz@gmail.com>
Date: Mon, 3 Aug 2020 11:41:23 +0200
Subject: [PATCH] Fix #4786 (#4787)

* Fix #4786

Fix #4786

* Update header.js
---
 core/modules/server/authenticators/header.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/core/modules/server/authenticators/header.js b/core/modules/server/authenticators/header.js
index 4d3894f1c..78ae6cb0a 100644
--- a/core/modules/server/authenticators/header.js
+++ b/core/modules/server/authenticators/header.js
@@ -14,7 +14,7 @@ Authenticator for trusted header authentication
 
 function HeaderAuthenticator(server) {
 	this.server = server;
-	this.header = server.get("authenticated-user-header").toLowerCase();
+	this.header = server.get("authenticated-user-header") ? server.get("authenticated-user-header").toLowerCase() : undefined;
 }
 
 /*