Writing this recommendation here so that others in the future when searching the problem will understand how to solve it.
First, the problem is not Dgraph’s. But from Google. All Chromium-based browsers are limiting HTTPS service calls to other services without a TLS certificate. Google’s reasons are security based and beyond our control. It is not possible to do anything on our side.
The workaround is to use Firefox instead of any other Chromium-based browser. This is not just for Ratel, but for Tour tutorials as well.
e.g:
If you connect to https://play.dgraph.io/?latest and use a local server http://localhost:8080 - Chromium will block the connection. Then use Firefox instead.
If other problems like CORS exist. Keep using Firefox, but use an extension like “CORS Everywhere” or “Allow CORS: Access-Control-Allow-Origin”. But in general only changing the browser will solve.
Other solution is just run Ratel locally via Docker.