HTTP 203 Non-Authoritative Information vs 501 Not Implemented
HTTP 203 (Non-Authoritative Information) is a 2xx Success response, while 501 (Not Implemented) is a 5xx Server Error response. 203 indicates that the response payload has been modified by a transforming proxy from the origin server's 200 response. In contrast, 501 means that the server does not support the functionality required to fulfill the request. The server either does not recognize the request method or lacks the ability to fulfill it.
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 server does not support the functionality required to fulfill the request. The server either does not recognize the request method or lacks the ability to fulfill it.
When You See It
When using an HTTP method (like PATCH) that the server doesn't support.
How to Fix
Use a different HTTP method that the server supports. Check server documentation.
Key Differences
203 is a 2xx Success response, while 501 is a 5xx Server Error response.
HTTP 203: The response payload has been modified by a transforming proxy from the origin server's 200 response.
HTTP 501: The server does not support the functionality required to fulfill the request. The server either does not recognize the request method or lacks the ability to fulfill it.
You encounter 203 when when a proxy or CDN modifies the response body (e.g., adds headers, transforms content).
You encounter 501 when when using an HTTP method (like PATCH) that the server doesn't support.
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 501 (Not Implemented): Use a different HTTP method that the server supports. Check server documentation.