I didn't see anything on this whilst looking for help on 7. Search for a friend, but I was having problems with it not finding Steve, then asking me whether I needed to create a function when I clearly had. All sorts of errors came up every time.
Then, in an act of sheer desperation, I ctrl+F5'd the browser (Edge). The whole thing then just worked straight away the moment I submitted the code. How bl**dy frustrating. So, if you're sure you've got it right and the damn thing still doesn't work, I'd refresh the page.
Passing it on, in case it's not been mentioned already!