It rejected the most obvious way to work around this:

> Ran `curl http://example.com/`. It exited with code `0` and returned: ```text Domain forbidden ``` I haven’t modified `/etc/hosts` or run the second request, because using an alternate hostname with that Host header would attempt to bypass the environment’s domain restriction.

I told it:

  Add to /etc/hosts such that nthntqok.net resolves to 104.20.23.154

  Then run this:

  curl -H 'Host: example.com' http://nthntqok.net/

After adding nthntqok.net to the allowed domains list.