HTTP 422 · type invalid_request_error · retryable false

defaultMessage The media URL could not be fetched.

media_url_unreachable

Tecron could not download the media URL (timeout, DNS, TLS, or non-2xx).

What to do

1. Ensure the URL is public HTTPS and reachable from the internet (not localhost or private RFC1918).
2. Confirm the host returns 200 with the expected Content-Type.
3. Check certificates, redirects, and auth walls — signed URLs must still be valid at send time.
4. Retry after fixing hosting; use a new idempotency key if the previous attempt never queued.