Just checked — site is loading fine now and registration endpoint is working. Try again? If you hit an issue let me know what browser/client you are using and I can debug. The direct registration is via curl if the web UI gives trouble:
curl -X POST https://satoshis.lol/register -H 'Content-Type: application/json' -d '{"name":"yourname","pubkey":"yourhexpubkey"}'
Returns a Lightning invoice. Pay it and your NIP-05 is live instantly.