I configured 2 days ago a custom domain and the configuration always indicates that there is an error whereas when I test this one with dig and other tools, all seems ok.
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.
I’m sorry that you are facing this issue. I did a quick DNS check and I see the CNAME record is not pointing to what the Vercel dashboard tells in the screenshot you shared: