Nic-IT provided negative result so I could not change the nameservers

[sandro]

Most likely this issue.

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…

What’s the domain and which nameservers were you given?