I’m using vercel domain’s API to let users add domain on the platform so that the application can load on their domain. The problem is many times the DNS Records response from add-domain API is totally different than what records needs to be added on the domain provider DNS.
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.