I tried to add kamontat.in.net
domain in netlify dns but the error said, Subdomains are not supported as DNS zones
Yup, in.net looks like a domain to us, and our DNS hosting does not handle subdomains. While this may be a bug (did you buy “kamontat.in.net” from a registrar? If not, it’s not a bug…)
Unfortunately, you won’t be able to use our DNS hosting for that domain. You can still use our CDN though, following this guide: Configure external DNS for a custom domain | Netlify Docs with any other DNS host.
Thanks! I’ve gotten a bug filed but do not expect the behavior to change in the nearterm, so my advice about using a different DNS host such as namecheap itself still stands.