HTTP 401 Unauthorized
Plain-English meaning
The request lacks valid authentication credentials.
Why it happens
The server requires auth, but token, session, or signature is missing or invalid.
Common causes
- Expired JWT or OAuth token
- Authorization header dropped at proxy boundary
- Wrong audience/issuer claims
- Clock skew breaks signed token validation
What to check first
Inspect WWW-Authenticate header and auth middleware logs; verify token expiration, issuer, and scope.
How to fix it
Refresh or reissue credentials, fix token validation config, and preserve Authorization headers through proxies.
Example signal
GET /api/orders Authorization: BearerHTTP/1.1 401 Unauthorized
Related links
404 · 429 · 500 · 502 · 503 · 504 · Cloudflare 522 · Nginx 499 · ERR_CONNECTION_REFUSED
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