CSP diagnostic: If Firestore requests are blocked you will see a message and a header snippet to add to your server below. If your server sends a restrictive CSP header, the only fix is to update that server header (instructions below).
Status: unknown (running test)
If you host from a server that sets Content-Security-Policy, add this header (copy below):
Examples were provided earlier. If your host (e.g. Neocities) does not allow custom response headers, move the site to Netlify, Cloudflare Pages, or run a local server for testing.