Vercel DNS -> Payload custom domain SSL error

Geting SSL_ERROR_NO_CYPHER_OVERLAP with a CNAME custom domain in Vercel. I have opened a ticket with Vercel but I was wondering if anyone had experienced this already. I feel like I am missing somehthing obvious here.

cms.domain.tld = payload cloud

domain.tld = vercel

I never did get vercel subdomains working. The automatic dev staging etc. works fine but anything else would not. I'm sure I'm missing something but the documentation wasn't helpful. For anyone finding this, I just set up Cloudflare and do it there instead.