# 21609: Invalid 'StatusCallback'

Log Type: TWILIO

Log Level: ERROR

## Description

Twilio returns this error when the `StatusCallback` URL you provided is not a valid URL.

### Possible causes

* The StatusCallback value is not a valid URL.
* The URL exceeds the 4000-character limit.
* The URL is missing one or more components of a fully qualified URL (protocol, hostname, file path, or properly URL‑encoded query parameters).
* The URL is not reachable by Twilio over the public internet.
* The URL's hostname is invalid (for example, contains underscores), which violates the Messages API StatusCallback parameter requirements.

### Possible solutions

* Submit a fully qualified URL that includes all of the following: protocol (http:// or https://), hostname, file path, and properly URL‑encoded query parameters.
* Ensure the URL length doesn't exceed 4000 characters.
* Ensure Twilio can reach the StatusCallback URL over the public internet.
* Ensure the URL contains a valid hostname; underscores are not permitted for the Messages API StatusCallback parameter.

## Additional resources

* [Messages resource](/docs/messaging/api/message-resource)
* [Track the Message Status of Outbound Messages](/docs/messaging/guides/track-outbound-message-status)