Name servers are 'invalid' according to my registrar

[sdayman]

That alert about the name servers already “knowing” your domain might be the problem. This sounds like the usual requirement of .de registrars.

This the only tutorial I can find that addresses the issue. Maybe another @MVP remembers more.

Deprecated - Can't set nameservers - (Inconsistent Set of NS / Nameserver not authoritative)

This tutorial is deprecated in favour of Troubleshooting zone setups - Nameservers · Cloudflare DNS docs Related content:

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The issue: This is common to European registries, the registry tries to validate the nameservers you are adding. This is most likely caused by the domain previously being active in another Cloudflare account with different nameservers. They therefore believe that the wrong nameservers are responding so prevent you from adding the new nameservers. What to do about i…