> ## Documentation Index
> Fetch the complete documentation index at: https://docs.wavix.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Callback URL is invalid

## Error description

Wavix couldn't validate the `callback_url` parameter in your Send message request.

## How to fix it

Check that the `callback_url` parameter in your Send message request is correct and starts with http\:// or https\://.