# 57004: 'Category' is empty

Log Type: APPLICATION

Log Level: ERROR

## Description

This error means the request included `Category` without a value. Twilio returns this error for Messaging requests when `Category` is empty or not specified.

### Possible causes

* `Category` was omitted from the request.
* `Category` was sent as an empty string or blank value.

### Possible solutions

* Pass a valid, non-empty `Category` value in the request.
* Validate required fields before sending the request so blank values are rejected earlier. Twilio validates provided parameters and surfaces the exact error, causes, and suggested solutions in error logs.

#### Additional resources

* [Debugging Your Twilio Application](/docs/usage/troubleshooting/debugging-your-application)
* [Programmable Messaging](/docs/messaging)