---
title: "HTTP Error 401.1 - Unauthorized"
slug: "http-error-4011-unauthorized"
updated: 2023-06-14T07:46:08Z
published: 2023-06-14T07:46:08Z
canonical: "docs.biztalk360.com/http-error-4011-unauthorized"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.biztalk360.com/llms.txt
> Use this file to discover all available pages before exploring further.

# HTTP Error 401.1 - Unauthorized

Error Type: Constantly challenged by username and password - HTTP Error 401.1 - Unauthorized: Access is denied due to invalid credentials

:::(Warning) (Warning)
This article is not relevant for users using IIS version greater than 6
:::

When you get a repeated authentication request even when you type the correct credentials and ending up with a **401.1 Unauthorized **after a few tries, there is a big chance that the user running the BizTalk360 service doesn't have the necessary permissions to create the SPN entries in the Active Directory needed for calling the back-end database with the logged on credentials. The following Microsoft KB describes this problem and explains the solution.

You receive an "**HTTP Error 401.1 - Unauthorized: Access is denied due to invalid credentials**" error message when you try to access a Web site that is part of an IIS 6.0 application pool


Follow the article by creating the necessary SPN entries and the problem should get resolved.