401 status code: What is '401 Unauthorized'

What is '401 Unauthorized'? Learn how to use and/or fix this HTTP status code, with free examples and code snippets. What is the 401 HTTP Status Code? The 401 Unauthorized is an HTTP status code that indicates the request to the web server requires user authentication. The full name is “401 Unauthorized” or “HTTP 401,” as defined in the HTTP specification RFC 7235. The 401 code is in the class of 400 codes that signify a client-side error, meaning the requesting client did not provide a valid request. To Fix the 401 Unauthorized Access Error, it’s crucial to understand the root causes and ... The "401 Unauthorized Error" is a standard HTTP response status code that indicates that a request sent to a server cannot be completed because it lacks valid authentication credentials. Learn the difference between 401 and 403 status codes, and when to use them for authentication and authorization errors. See answers from experts and users, with examples and references to RFCs.