Thumbnail images go to embarrassing page

I’m hating wp a LOT right now. been working for TWO DAYS to figure out why thumbnail images, when clicked on, go to a page that says “oops this is embarrassing.” No, it’s iinfuriating. And when I link it to media file instead of attachment page, clicking on it just has the plain image jammed in the corner of a white page. oh, so attractive. Then I spent 10 minute just trying to find support, but it didn’t want my question because even tho I have FOUR blogs in wp I don’t host on their domain. I see nothing online for a solution fro this. This is a simple image gallery. It shoudl be up & running in 5 minutes! I’ve lost at least 10 hours on this!! Absurd!