Web build doesn't load in browser

Just trying a web build for the first time. The project opens in FireFox and shows the Unity window, but the loading bar never fills.

9176156--1277708--upload_2023-7-27_18-53-3.png

Go check the browser log!

Yeah, I think I found that. Restarted conversation in correct WebGL sub forum, although I’m told the error messages are non-descriptive.