Proceed to Checkout Directs to an Error page

Are you using a PayPal extension or PayPal standard that come with WooCommerce core? Is your PayPal account configured correctly? https://docs.woocommerce.com/document/paypal-standard/

Have you tried disabling all plugins except for WooCommerce and switching to a default theme for testing? https://www.ads-software.com/support/topic/how-to-debug-issues-after-updates

And lastly, if none of the above steps help, please post your system status report here: https://www.ads-software.com/support/topic/before-posting-gather-the-following-details