HTTP 401
Unauthorized
Client Error
What does "HTTP 401 Unauthorized" mean?
Plain-English Meaning
Authentication is required and has failed or not been provided. Despite the name, it's really about authentication, not authorization.
Common Causes
- Missing or invalid login credentials
- Expired session token
- API key not provided
What Users Can Do
Log in again. Check your credentials.
What Developers Can Do
Return 401 with a WWW-Authenticate header. The client should retry with credentials.
Related Status Codes
400
Bad Request 403
Forbidden 404
Not Found 405
Method Not Allowed 408
Request Timeout 429
Too Many Requests
Bad Request 403
Forbidden 404
Not Found 405
Method Not Allowed 408
Request Timeout 429
Too Many Requests
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