PayPal had a couple issues earlier today which may explain all that. This one affected PayPal accounts and card payments using Braintree:
https://www.paypal-status.com/history/eventdetails/88108
...and this one affected their Payflow gateway, which affected card payments using PayPal Payments Advanced, Payflow Pro, and Payflow Link:
https://www.paypal-status.com/history/eventdetails/88111
Those issues should now be cleared up, so let us know if you see any continuing problems by now.