"An embedded page at ...'

I’m the developer of glowscript.org, where users can write, run, and save programs written in Python and transpiled to JavaScript in the browser. There are over 60,000 user accounts. Programs can use the VPython API to easily generate navigable real-time 3D animations. This works on all browsers and operating systems except, I just learned, Brave on OSX or Windows 10 (Brave does work on Android). I get the error “An embedded page at sandbox.glowscript.org says null”, and the error popup reappears as soon as I dismiss it. User programs are in fact executed in a sandbox that prevents programs from doing damage to other people’s work. This seems like a Brave bug, not a GlowScript bug, since there is no problem in other browsers. I certainly have no clue as to what GlowScript should do differently to prevent this bug.

Thanks for reaching out. I am not sure what the problem is.

I checked sandbox.glowscript.org and it seems to be a server problem (403). There are no other console errors, only the 403.

You should also try to disable Brave Shields(Lion head icon) in the URL bar.

Thanks very much for the rapid response. It is indeed the case that disabling Brave Shields lets the program run.

As the developer of glowscript.org, can you offer me any advice on what I would need to do for programs to work even with Brave Shields turned on?