In my case, I have a static site by GastbyJS on, so I need to bind subdomain for my firestore hosting project, here is my workaround.

On my first, I think it maybe relate about, it’s my DNS provider, but I miss a tip, netlify have been set up upon, so I need to set up on netlify.

  1. Visiting firebase/hosting panel and click “connect domain”
  2. copy verification on your clipboard
  3. Visiting netlify/Domains set you TXT record to verify your domain.
  4. wait for a few minutes
  5. verify on firebase panel
  6. Adding A records for two ip address
  7. done

It’s simple and easy, but it should be knowing DNS provider who is.

Remember, you need to add authorized domains for customize domain.