With the new version of Unity, I get an error when Joining a room while playing on WebGL browser:
"The object returned from unityloader.instantiate() should be stored in a global variable on window somewhere. (e.g. window.gameinstance = unityloader.instantiate(...)"
This is probably because the webgl template for Unity has changed and it doesn't have window.gameinstance anymore.
Edit [SOLVED]: It can actually be fixed by adding a "then" in the HTML createUnityInstance =>
....).then((unityInstance) => {window.gameInstance = unityInstance;});