HTTP 501 Not Implemented vs 504 Gateway Timeout
Both HTTP 501 (Not Implemented) and 504 (Gateway Timeout) belong to the 5xx Server Error category. 501 indicates 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. Meanwhile, 504 means that the server, acting as a gateway or proxy, did not receive a timely response from the upstream server.
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.
Description
The server, acting as a gateway or proxy, did not receive a timely response from the upstream server.
When You See It
When an upstream server is too slow to respond within the proxy's timeout window.
How to Fix
Increase proxy timeout settings. Optimize upstream server performance. Check for long-running queries.
Key Differences
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.
HTTP 504: The server, acting as a gateway or proxy, did not receive a timely response from the upstream server.
You encounter 501 when when using an HTTP method (like PATCH) that the server doesn't support.
You encounter 504 when when an upstream server is too slow to respond within the proxy's timeout window.
When to Use Which
For 501 (Not Implemented): Use a different HTTP method that the server supports. Check server documentation. For 504 (Gateway Timeout): Increase proxy timeout settings. Optimize upstream server performance. Check for long-running queries.