IONOS (1&1) — CNAME for chat.

1. Log in to IONOS → Domains & SSL → your domain → DNS.

2. Add record:

   • Type: CNAME
   • Hostname: chat
   • Points to: cname.vercel-dns.com

3. Save.

IONOS “default” vs external

If the domain uses external nameservers, edit DNS at that host (Cloudflare, etc.).