Unable to setup Netlify DNS on custom domain

Hello folks,

With regards to my site - https://avatars-ai-chat.netlify.app/
I need to delegate it to Netlify for my custom domain - https://avatars-ai.chat

However, under DNS Panel settings, the status is stuck as - Awaiting External DNS
And further error says:
“A DNS zone for this domain already exists on NS1, the DNS provider backing Netlify DNS
Please contact NS1 with the domain name for support.”

Please help me out of this situation as the purchased domain is dormant due to this and im unable to resolve this out.
I already have 2 other sites published using Netlify where in I used custom nameservers from below and did the same this time as well, but it is working :

Please help me resolved this issue at the earliest!

There are two ways to connect a custom domain to a Netlify site.

The external DNS keeps the DNS resolution with the existing provider - which is normally the domain registrar but not always.

If you are moving an existing domain name to Netlify DNS -especially if you have an email service configured for it - please be be sure to copy all existing records to Netlify before changing the name server (NS) records to point to Netlify. There is more about this topic here.

If you are using the external DNS method, the existing DNS records remain active so no records need to be copied.

Please let us know if there are other questions about this and we’ll be happy to answer.