I would like to use a domain I used in an old project from another Vercel account. However, I deleted that old project, and when I try to add my domain into my new project, I get the message:
This domain is linked to another Vercel account. To use it with this project, add a TXT record at _vercel.thedomain.com to verify ownership. You can remove the record after verification is complete.
Why is it requesting this verification? Because the project with this domain (name in printscreen) no longer exists, in my second account.
The domain troubleshooting guide can help with most custom domain configuration issues. You might be able to use that guide to solve it before a human is available to help you. Then you can come back here and share the answer for bonus points.
You can also use v0 to narrow down the possibilities.
You can go to your domain registrar (which appears to be public domain registry unless it’s a reseller) and add the TXT record there to verify your ownership