Any guesses as to why art from Fanart.tv can be had via browser, but not via scraper?

Through much trial and error, I think I'm finally starting to pin this one down. Kodi on the Nvidia Shield was failing to grab disc art, through the use of the likes of Artwork Beef. But Kodi itself still thought it was in fact succeeding. So it would display for me an invisible disc.

In an effort to bypass that rigamarole, I began using a Windows-based scraper called MediaElch, and it's clear I should have done this from the start. (Hopefully moving all of the data over to the Shield and having Kodi accept it as artwork is something I won't have to do one piece at a time.) But now that I have the app in front of me on a proper OS, I'm able to glean a little insight into the disc art problem.

MediaElch is trying to fetch disc art from Fanart.tv, in addition to a couple of other bits of art. Each one of those fetch attempts times out, fetching nothing. And yet if I browse Fanart.tv directly via a browser, I can find the artwork that way, no problem. So the issue seems to be that something is blocking artwork from being able to be downloaded through whatever means scrapers—at least the MediaElch and Kodi-based scrapers—are attempting to download them.

And since I have absolutely zero interest in manually searching for and downloading potentially thousands of individual art files, my obvious next step is to see if anyone knows what the heck may be going on here. For what it's worth, I've already tried this from a different network in a different household, and through a VPN. Whatever's preventing this from working is more fundamental than "Check your firewall/anti-virus software/power cable/tinfoil hat".

Edit: It may be that the reason the artwork is seemingly failing due to timeout is that I have not met MediaElch's criterion for "having movies stored in individual folders". MediaElch presents a second tab called "Extra Fanarts", and it might be that Discart, Thumb, etc. all are meant to fall under this category. But the only thing I ever see under this tab is "Support for extra fanarts is only available when your movies are stored in separate folders. Check the settings if you've stored your movies in separate folders already." Well, to make the app happy, I've done that. It doesn't seem to care. And there's nothing in the Settings that really stands out as something I'm supposed to be looking for if I've done what it asked and things still aren't downloading.