Cloudflare DNS seems to be down at the moment :-) The API calls return "null" as the result like `'{"result":null,"success":true,"errors":[],"messages":[],"result_info":{"page":1,"per_page":100,"count":0,"total_count":0,"total_pages":1}}'`
It might be irrelevant but their core product (of returning results), i.e. dig google.com @1.1.1.1 seems to be working fine here.
Well, it turns out https://developers.cloudflare.com/api/operations/dns-records... now returns "null" in result . I think it returned empty array before.