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4xx Client Error

HTTP 401 Unauthorized

The request needs valid authentication credentials.

Check a URL's HTTP status

What 401 means

Despite its name, 401 means unauthenticated. The server includes a WWW-Authenticate header describing how to authenticate.

Common causes

  • Missing or expired login session or token.
  • Wrong API key or password.

How to fix it

  1. Sign in again or refresh the access token.
  2. Check that the Authorization header is sent correctly.

SEO impact

Search engines cannot index pages behind a 401. Keep public content outside authentication.

How to check a status code

Enter a URL in the HTTP Status Checker to see its status code, every redirect hop, and response time. For redirect-heavy pages, the Website Speed Test shows how much time redirects add.

FAQ

What does HTTP 401 mean?
401 Unauthorized is a 4xx client error status code. The request needs valid authentication credentials.
What causes a 401 error?
Missing or expired login session or token. Wrong API key or password.
How do I fix HTTP 401?
Sign in again or refresh the access token. Check that the Authorization header is sent correctly.

Defined in RFC 9110.

Other 4xx client error codes

400 Bad Request403 Forbidden404 Not Found405 Method Not Allowed406 Not Acceptable408 Request Timeout409 Conflict410 Gone413 Content Too Large414 URI Too Long415 Unsupported Media Type418 I'm a teapot422 Unprocessable Content425 Too Early429 Too Many Requests431 Request Header Fields Too Large451 Unavailable For Legal Reasons