Quickbooks has asked me to reconnect PayPal but after logging in and initially saying "you're all ready" I'm then told "We're sorry, we couldn't confirm it's you"

I am able to log into PayPal normally away from Quickbooks, but I'm not being allowed to reconnect this account. Any help please? I've tried disconnecting PayPal completely from Quickbooks, but when I go to add it again, I'm given the same message.