PayPal woocommerce plugin error

Hi, for a few weeks I’ve been having a problem on a woocommerce website with payment via PayPal.
the error appears after I select the payment method and the URL becomes PayPal, this is the message on the screen: “a system error has occurred. Please try again later.”
Unfortunately it’s too generic an error and I can’t understand what the problem is. can someone help me? Thanks, Danilo