# 40000: Bad request

Identifier: `bad_request`



The request was rejected because it was invalid and could not be processed.

## What you should do

Correct the request and resend it. 40000 is the generic code for a request Ably could not process, so start from the accompanying message, which states what was wrong.

## Why it happens

The request was malformed or otherwise invalid in a way that doesn't have a more specific error code. The accompanying message describes the specific problem.

## What you'll see

The error is reported with code 40000 and HTTP status 400. The message describes what made the request invalid.