Add my existing custom domain to my project

My netlify site name. beamish-speculoos-5daac5.netlify.app
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I have been waiting for 32hours after following the instruction to do the set up.
It still shows " Domain helpingyou.hk is already registered and not owned by your Netlify account.
To verify ownership, add the following TXT record to your DNS provider at the root level."

Please advice what’s wrong with it/

can anyone help?! it’s been 40hours after setting up. still cannot verify

I’ve routed this request to our helpdesk, we’ll follow up via email.