I've been having a dickens of a time with one of the grand's laptops regarding one, and only one of her online classes. For her Art class, the pages would load, but not the text. I went nuts, clearing the browser, removing privacy options, removing browser extensions, etc. Thinking it might be a bad cookie, I removed all the cookies from the browser, knowing a new one would be put in at each, and every website visited.
I was on the right track, because there was a damaged cookie file, however, unbeknownst to me, her mother had shut off accepting all cookies. My setting is on "do not accept third party cookies". Since the computer is being used by the grands, especially the youngest, their mom decided to go in, and turn on all the safety protocols she could find. While enabling some of the safety features is a good thing, especially to protect kids, BUT enabling too many, OR all the strictest ones, can actually prevent the browser from working.
Fortunately, when looking at the scripts for the webpage, it mentioned a problem with cookies. That sent us looking at the cookie settings. That's how we found the cookie settings had been set too strict, and it wasn't allowing a new cookie file to load from the class's website. Of course, without the class's cookie, the page wouldn't load. Now, the cookie settings are correct, a new undamaged cookie file has been loaded, and all is well.
This has been driving me nuts for over a week.