HTTP 203 Non-Authoritative Information vs 401 Unauthorized
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HTTP 203 (Non-Authoritative Information) is a 2xx Success response, while 401 (Unauthorized) is a 4xx Client Error response. 203 indicates that the response payload has been modified by a transforming proxy from the origin server's 200 response. In contrast, 401 means that the request requires user authentication. The response includes a WWW-Authenticate header indicating the authentication scheme.
Description
The response payload has been modified by a transforming proxy from the origin server's 200 response.
When You See It
When a proxy or CDN modifies the response body (e.g., adds headers, transforms content).
How to Fix
Check if a proxy is modifying the response. Access the origin directly if you need the original content.
Description
The request requires user authentication. The response includes a WWW-Authenticate header indicating the authentication scheme.
When You See It
When accessing a protected resource without credentials or with expired tokens.
How to Fix
Include valid authentication credentials (API key, Bearer token, Basic auth) in the Authorization header.
Key Differences
203 is a 2xx Success response, while 401 is a 4xx Client Error response.
HTTP 203: The response payload has been modified by a transforming proxy from the origin server's 200 response.
HTTP 401: The request requires user authentication. The response includes a WWW-Authenticate header indicating the authentication scheme.
You encounter 203 when when a proxy or CDN modifies the response body (e.g., adds headers, transforms content).
You encounter 401 when when accessing a protected resource without credentials or with expired tokens.
When to Use Which
For 203 (Non-Authoritative Information): Check if a proxy is modifying the response. Access the origin directly if you need the original content. For 401 (Unauthorized): Include valid authentication credentials (API key, Bearer token, Basic auth) in the Authorization header.