HTTP 401 Unauthorized — Authentication Required

HTTP 401 Unauthorized means authentication is required. The client must provide valid credentials. This guide covers everything you need to know about this topic, including common causes, step-by-step solutions, and answers to frequently asked questions.

Here are the key things to understand: Status: 401 Unauthorized. Category: 4xx Client Error. Authentication required or failed. Response includes WWW-Authenticate header. Understanding these fundamentals will help you diagnose and resolve this issue more effectively.

The most common reasons this occurs include: No authentication credentials provided. Access token expired. Invalid username or password. Bearer token is missing or malformed. Identifying the root cause is the first step toward finding the right solution.

To resolve this, follow these recommended steps: Check if Authorization header is included. Verify the token has not expired. Refresh the access token if using OAuth. Confirm credentials are correct. If these steps do not resolve the issue, consider consulting additional resources or a qualified professional.

This article is part of our HTTP Status Codes collection on Error Codes Wiki. We provide comprehensive, up-to-date information to help you find solutions quickly.