# What are the CLB error codes?

The error codes of CLB basically follow the HTTP standards.

## Client errors, return 4XX

* 400 Bad request: Your browser sent an invalid request.
* 403 Forbidden: Request forbidden by administrative rules.
* 408 Request Time-out: Your browser didn't send a complete request in time.

## Server errors, return 5XX

* 500 Server Error: An internal server error occured.
* 502 Bad Gateway: The server returned an invalid or incomplete response.
* 503 Service Unavailable: No server is available to handle this request.
* 504 Gateway Time-out: The server didn't respond in time.