Error 401

That means the page you were trying to access cannot be loaded until you first log in with a valid user ID and password.The Web site that you try to view uses Integrated Windows authentication. The application pool for the Web site recycles during the authentication process. The server generating a 401 response MUST send a WWW-Authenticate header field¹ containing at least one challenge applicable to the target resource.

Sometimes it can happen like this also: we gave the credentials in our office computer and it showed the web page, but when we  tried it with exact same credentials in some other place it showed the message “401 Authorization Required”. It happened because that specific web page can only be seen on some particular computers. Your current computer’s address is not authorised to see the web page.

 

More on HTTP Error 401 there are some specifications on it. Likewise:

• HTTP 401.1: Denied by invalid user credentials
• HTTP 401.2: Denied by server configuration
• HTTP 401.3: Denied by resource ACL
• HTTP 401.4: Denied by custom ISAPI filter
• HTTP 401.5: Denied by custom ISAPI/CGI Web application

what is the reason of Error 401?

When we encounter HTTP Error 401, we can’t see the specific web page. If we are looking for a file to be downloaded then it can’t be downloaded until the problem is resolved.

How to Fix it?

1. First of all we have to check whether the URL (Universal Resource Locator) is correct or not. If the URL is wrong then we have to type the correct URL and try again. Sometimes if we are going to a particular URL via some link then there is a possibility that the link is wrong. So we have to take care of that also.
2. If the URL is correct and still we can’t access the page then might be we don’t have permission to access the web page.
3. In this context if we are authorised to see the page then we have to find the login area and have to give correct credentials.
4. If the site we are visiting doesn’t require any authorization and still it’s showing the message then there must be some mistakes. In this situation we should contact the web master of that site. Generally the email ID of web master is [email protected] (here replace example.com with the specific web site name).
5. Sometimes after giving proper credentials, we still see the message. Then there is a possibility that the web server is configured to deny some HTTP traffic. Which means it can be seen  only by some well known web browser. Whenever automated connections are trying to view the page it is configured to display the “401 Authorization Required” message. Though it is a rare one.