# 30109: Callback URL is invalid

Log Type: APPLICATION

Log Level: ERROR

## Description

This error occurs when the `CallbackUrl` in your Link Shortening domain configuration isn't a valid URL. Click event data is sent to this callback URL after a recipient clicks a shortened link.

### Possible causes

* The `CallbackUrl` is missing a protocol such as `http://` or `https://`.
* The hostname is invalid, incomplete, or malformed.
* The path or query string contains characters that aren't properly URL-encoded.
* You entered an invalid **Click tracking callback URL** in the Console, or sent an invalid `CallbackUrl` parameter in the request.

### Possible solutions

* Submit a fully qualified `CallbackUrl` that includes the protocol, hostname, and any required path.
* If you configure Link Shortening in the Console, update the **Click tracking callback URL** and save the domain configuration again.
* If you configure Link Shortening with the API, send a corrected `CallbackUrl` in a `POST` request to the Link Shortening domain's Config subresource.
* URL-encode special characters in the path and query string before you save or submit the callback URL.

#### Additional resources

* [Link Shortening](/docs/messaging/features/link-shortening)
* [Link Shortening Onboarding Guide](/docs/messaging/features/link-shortening/onboarding-guide)
* [Webhooks (HTTP callbacks): Connection Overrides](/docs/usage/webhooks/webhooks-connection-overrides)