invalid_url

The webhook URL is not allowed. The message is the same whatever rule refused it.

HTTP 400.

Likely causes:

• Not https://.
• The host is localhost, *.localhost, *.internal or *.local, or the URL carries a username or password.
• The host is, or resolves to, a non-public address (loopback, private, link-local, carrier-grade NAT, multicast, reserved), or cannot be resolved.
• Re-enabling an endpoint whose URL breaks these rules.

What to do: Use an https URL whose host resolves only to public internet addresses.

Retry: No. The same request gets the same answer; change something first.

Listed under Webhooks in Errors. Send the error’s requestId to support and we can find the request.