What Is the 401 Status Code? (Unauthorized)

The server is telling you it doesn't know who you are — unlike 403, which means it knows and still refuses. The response usually carries a WWW-Authenticate header naming the scheme (Basic, Bearer, etc.). In short, 401 status code is the request lacks valid authentication credentials.

Scrapers hit 401 when a page or API sits behind authentication: a missing or expired session cookie, an absent or wrong API key / Bearer token, or a login the scraper never completed. Some sites also return 401 instead of 403 when an anti-bot layer decides the caller isn't a logged-in human.

Supply valid credentials for the scheme the server asks for — refresh an expired token, replay a logged-in session's cookies, or add the API key header. For authenticated areas, log in once and reuse the session instead of authenticating per request. When a 401 is really a disguised bot block on a public page, treat it like a 403: realistic headers, a clean residential IP, and a real-browser fingerprint via Web Unblocker.