PayPal is notoriously unpredictable about what it allows and how; but based on what I’ve experienced and been hearing about the latest payment issues, this particular situation looks like a problem with your accounts.
That sucks, because PayPal customer service is almost non-existent for most clients. One trick that has helped me when there as anything I can other than wait to see if access was restored: sign in to your Paypal account in the browser. Open the page where you want to make the purpose, using the same browser window.