4xx · Client error

HTTP 401 Unauthorized

Authentication is missing or invalid. Despite the name, this is about who you are.

Common causes and fixes

Send valid credentials or a fresh token.
A WWW-Authenticate header should say how to authenticate.

Example response

HTTP

HTTP/1.1 401 Unauthorized
WWW-Authenticate: Bearer realm="api"
Content-Type: application/json; charset=utf-8

{ "error": "Unauthorized" }

Look up the headers shown here in the HTTP headers reference.

Common questions

What does HTTP 401 mean?: Unauthorized. Authentication is missing or invalid. Despite the name, this is about who you are.
How do I fix a 401 error?: Send valid credentials or a fresh token. A WWW-Authenticate header should say how to authenticate.
Is 401 an error?: Yes. 4xx codes are client errors: The request contains a mistake or can't be fulfilled as sent.

Other 4xx codes