I am experiencing this same issue, but LSA is running.
I have tried Microsoft Edge (Version 90.0.818.51 (Official build) (64-bit)), Google Chrome (Version 90.0.4430.93 (Official Build) (64-bit)), Mozilla Firefox (88.0 (64-bit)), Vivaldi (3.8.2259.37 (Stable channel) (64-bit)) and Internet Explorer 11. Running on Windows 10 Pro Version 10.0.19042 Build 19042, All are giving the same results a blank grey screen.
I have stopped and started LSA Services, uninstalled and reinstalled RWC3. Disabled everything that would block the connection, even gave it permission in the browsers to access the site.