The 401 Unauthorized Error is HTTP status code error that represented the request sent by the client to the server lacks valid authentication credentials. It may be represented as 401 Unauthorized, Authorization required, HTTP error 401- Unauthorised. It represents that the request could not be authenticated. It consists of a
www-Authenticate header which contains the hint on how to authorize correctly.
401 Unauthorized Error Occur: This error may occur due to the reasons described below:
- It may occur client does not provide the proper authentication credentials to the server within the request time.
- It may occur when the server rejects the request of the client for some reasons even though the client provides proper authentication credentials.
- When the client is banned for some reasons by the server.
Methods to rectify the error: The 401 Unauthorized error can be fixed by using any of the following ways:
- Check The URL: Due to manual errors in typing the URL, the 401 unauthorized error may occur. Hence, by checking the URL and rectifying the mistakes in it will fix the 401 error status.
- Flush the DNS: Errors in DNS also creates 401 error status sometimes. Therefore, clearing the DNS will also rectify this error. In Windows, the DNS can be flushed by typing ipconfig/flushdns in the command prompt and clicking on ENTER.
- Clear Browser Cookie: In some situations, the cookies may not work smoothly leading to the improper server authentication. Thus, by clearing the cookies, the error can be rectified.
- Logging out and Logging in again: This error may also occur during the maintenance time of the websites. Therefore, visiting the website and logging in again by providing the credentials may also rectify this error.
- Website mistake: A few times all the above things are good or accurate but still you will get the 401 Unauthorized Error, that is mistake of the website. That time you need to contact the webmaster of that website and inform that the server is down. You can email them at
firstname.lastname@example.org the webmaster.com with the website or you can see the contact us option on any website through that you can inform them.
Some other ways of 401 Authentication error: This error can occur in the below forms also:
- 401.1: This error represents that the login has failed due to some reasons.
- 401.2: This error represents that the login has failed due to server configuration.
- 401.3: This eror represents that the login has failed due to ACL(Access-control list) on resource.
- 401.3: This eror represents that the the authorization has been failed by the filter.
- 401.501: This error represents that too many requests has been generated by the client i.e. maximum request limit has been reached by the client.
- 401.502: This error occur when any specfic client(sam IP) request multiple times on a single server that the dynamic IP Restriction Concurrent request rate limit reached. Then this error will occur
- 401.503: This error represents that the IP address of the client is in the deny list of IP restrictions on the server-side.
- 401.504: This error represents that the Host name of the client is in the deny list of IP restrictions on the server-side.