Interesting - just tried it in Opexa GX and had no issue. Not sure what the issue would be, perhaps just try in different browsers/different computer if you really want to try it. Sorry for that!
This happens to some games when using the itch.io Randomizer (random game) feature. I'm not sure why though. It works when you go to the actual game page. I'm using Brave web browser on Windows 11.