I'm not sure if you can help me with this one but I've exhausted all other options so thought I would give it a shot.
A user on one of our clients' sites is trying to make a purchase one of our training courses through WooCommerce, so they add it to cart, put all their info in the checkout, go through to PayPal, confirm all that info and finally hit 'Pay Now'. The loading icon appears and after a few seconds they get an error through from PayPal saying: "Things don't appear to be working at the moment. Please try again later."
Other payments for different products have gone through in the time that they have been trying to make their purchase, and we're able to make a purchase of the same item they are trying to buy no problem (albeit with a 99.9% discount code). The customer has also asked a colleague to try make the same purchase using different payment details without any luck. Also I should note that the product in question was purchased successfully by a different customer a few days ago.
I was just wondering if this was something you had seen before or could help with in any way - so sorry if not!!