What to check if High Fidelity displays a blank screen.
First, please make sure you're using a compatible device and web browser. Using an incompatible device or browser can result in a blank screen.
If you have been working on a custom map and are seeing a blank screen when trying to use it, please try a hard refresh of your browser window. Please also be aware that any custom map must be hosted on a CORS-enabled website or it will appear blank.