# 21609: Invalid 'StatusCallback'

Log Type: TWILIO

Log Level: ERROR

## Description

This error occurs when the `StatusCallback` value in your Message request isn't a valid URL. Use a fully qualified public URL with a valid hostname. Keep the URL at 4000 characters or fewer.

### Possible causes

* The `StatusCallback` value isn't a valid URL.
* The URL is longer than 4000 characters.
* The URL is missing part of a fully qualified address, such as the protocol, hostname, or path.
* The query string includes characters that aren't properly URL-encoded.
* The hostname is invalid. For example, it contains underscores.
* The endpoint isn't publicly reachable.

### Possible solutions

* Set `StatusCallback` to a fully qualified `http://` or `https://` URL.
* Use a valid hostname and remove unsupported characters such as underscores.
* Shorten the URL so it stays within the 4000-character limit.
* URL-encode query parameters before you submit the request.
* Make sure your endpoint is reachable from the public internet.
* Test with a temporary public webhook endpoint to confirm that Twilio can send callbacks. If that test succeeds, review your application logs, firewall rules, authentication requirements, and SSL configuration on your original endpoint.

#### Additional resources

* [Messages resource](/docs/messaging/api/message-resource)
* [Track the Message Status of Outbound Messages](/docs/messaging/guides/track-outbound-message-status)
* [How to Test and Troubleshoot Twilio Messaging StatusCallback Failures](https://help.twilio.com/articles/43659166532123)