The issue is this
$ whois bishopscourtfarm.org | grep DNSSEC
DNSSEC: signedDelegation
Netlify does not support DNSSEC as noted here and here.
If you wish to use Netlify DNS:
- Remove the Netlify name servers, replacing them with those of your registrar.
- Disable DNSSEC
- Once disabled, follow the procedure for adding the domain to Netlify again.
If you wish to have DNSSEC enabled:
- Remove the Netlify name servers, replacing them with those of your registrar.
- Remove the domain from Netlify DNS.
- Configure the domain using external DNS configuration