I get a white screen when opening the editors.

editors stuck on 'Wait a Moment' screen.

Is there something i need to add or a security setting that needs to be enabled or a page that needs unblocking.

Do I need any special configuration on my school firewall?
What domains need to be unblocked to allow the micro:bit editors to work?

The simulator is missing when I load the editor


Each editor has different requirements. Here is a full list of domains that you would have to whitelist on any firewall configuration.

PXT / MakeCode/Javascript Blocks Editor:


Touch Develop:

Code Kingdoms:

Python Web Editor (

Python Web Editor (