I'm having the same problem. It appears to be related to something with Chrome and Firefox. My WeatherSTEM page loads correctly on Edge, the Samsung browser on a friend's Galaxy, and Safari on iPhones. But it never loads the actual data when using Chrome or Firefox on Windows 10, or Chrome from an Android phone.
Still testing my setup so it's currently inside with the lense cover on, but should show a black image and about 72 degrees if loaded correctly. On Chrome and Firefox it has a blank (white) image and shows 32 degrees.
One of the problems with some browsers is caching. Clear all the caches and restart the browser. That might clear you up.
I've done that several times. It is not a cache problem. There is something wrong with the website. It loads the initial content but then does not repopulate with the current data. You can see the exact same "blank" page with a white picture and 32 degrees for a split second when the page loads correctly on other browsers. For some reason the part of the website code that loads the current data is not working in Chrome or Firefox.
Interestingly when I use developer tools I see 2 errors and three warnings in Chrome, and 44 errors and 6 warnings in Edge. There were also 7 "issues" in Chrome developer tools and it gave an option to reload the page in the Chrome developer tools. When I reloaded the page from Chrome developer tools it showed the page correctly. Now if I use a new tab in chrome the page also loads correctly. The page still does not load correctly on my phone or a second computer on Chrome that I have not messed with developer tools on.