Cloudflare GraphQL introspection doesn't work

My question:
Trying to auto-fetch Cloudflare’s GraphQL schema, however it does not work and not much way to debug further.

Details (like screenshots):
Looking at the console, the request has been successfully fulfiled and a JSON is returned. Thus not sure what went wrong.

I’ve already tried:
Other apps like Insomnia that actually works.

I’m also experiencing the same issue.