I'm sorry, but you're mistaken.

It was GoDaddy who used to require the use of a proxy server (their own) for making connections to PayPal (over CURL). Zen Cart had to be coded to support that requirement many years ago. Since then GoDaddy has finally decided to remove the need for a proxy server, but has even gone so far as blocking traffic that even *attempts* to use their old proxy server.

Since your site was set up to use the proxy, that's what was causing you the errors.

It's not a PayPal issue. It was/is a GoDaddy issue.