ACME DNS API and Cloud DNS

[heitbaum]

I have a number of domains at 

https://console.cloud.google.com/net-services/dns/zones?referrer=search&project=abc-abc-123

one of which is “abc.com”

But when I run https://acmedns.googleapis.com/v1/acmeChallengeSets/abc.com

I get the following error.

{
  "error": {
    "code": 404,
    "message": "Domain abc.com is not managed by Google Domains.",
    "status": "NOT_FOUND"
  }
}

Can someone shed some light on this? How to make it work.