I tried but i can't, i use godot too. You have to zip exe with pck file to distribute for windows. Export as html5 and let play in browser.
Viewing post in Escape The Lab jam comments
that's because you can't run locally the html5 file. You need a server to do it. If you click the g5 icon on top right of the godot it will run with a local server on your browser.
At the jam page when you submit you have to upload a zip with all the html5 folder content inside. I don't know if you can change the page now but try to reach the organizers