Ebay is certainly not free from glitches, so, who knows.

If the item arrived today you still have plenty of time to leave feedback if the item didn't arrive very late.

Try again tomorrow, and if it still does not work, you could contact eBay via live chat, although I doubt they would be able to solve your problem.

Sometimes I get the usual "it is not you; it is us" when some pages do not work, but soon after refreshing them they work.