Your PayPal has unfortunately expired as a payment method.
As the payment method cannot be saved permanently for security reasons, please delete it once and add it again as follows:
In your customer account:
Under the payment methods option, delete the payment method using the X on the right.
In your basket:
Click on "Change" next to the payment method
Then select the desired payment method in the new window
Confirm the new payment method with "Select this payment method"
Please note it may be necessary to verify again via PayPal. You will now be able to pay as usual via PayPal, or you can use one of the other payment methods at any time.