Look up a Rails HTTP Status Code
401 - Unauthorized
Rails HTTP Status code
:unauthorized
When to use status code 401
Similar to 403 Forbidden, but specifically for use when authentication is required and has failed or has not yet been provided. The response must include a WWW-Authenticate header field containing a challenge applicable to the requested resource. 401 semantically means "unauthenticated", i.e. "you don't have necessary credentials".