What site? What OS? If windows, home or pro and what security software are you running besides MS Defender?

Here is an example site (but any site presenting maps has either this message or a blank screen) https://experience.arcgis.com/experience/028de5f59b014757bda5cc2444d1f0c9

I have windows 10 pro, 64 bit, version 22h2 up to date.

Worked fine one day and then it didn't. Only difference I can see in about:config are two new lines marked web2gl that are checked as true