Use this little website to test if a URL is setup correctly to work with CORS.
Shareable link: https://cors-test.codehappy.dev/?method=get&origin=https%3A%2F%2Fcors-test.codehappy.dev%2F&url=https%3A%2F%2Fwww.akitaonrails.com%2F.well-known%2Fnostr.json
It does not have the access-control-allow-origin header set to *. Without this header, requests from other domains cannot be made to it via a users browser.
If you have access to the server for the URL, you'll need to modify it to add the access-control-allow-origin header. If you do not have access, you'll need to upload the file somewhere else.
These are the response headers received when making the request.
age: 0
cache-control: public,max-age=0,must-revalidate
cache-status: "Netlify Edge"; fwd=miss
cf-cache-status: DYNAMIC
cf-ray: 9bacffd8c4d4eb04-ORD
connection: keep-alive
content-type: text/html; charset=utf-8
date: Thu, 08 Jan 2026 16:16:27 GMT
server: cloudflare
strict-transport-security: max-age=31536000
transfer-encoding: chunked
x-nf-request-id: 01KEF6A8YJ08G506R830CMCTV8
CORS tester was built by @mscccc. The code is available on GitHub. Sponsored by HTML/CSS to Image.