That link does not resolve this problem. Essentially when you request a refund in your shopping cart. It calls the Paypal API and instructs it to refund. Paypal denies as no balance in Paypal funds. It should default from bank account or card registered on Paypal account.
We have had the same problem with Paypal. It's a popular issue and loads of requests for help on the web, but no solution from Paypal.
I personally contacted Paypal twice and on both occasions they closed the ticket with no success.
ACH means automatic clearing house.
Essentially unless you have credit in your Paypal balance there is an issue in authentication, so Paypal won't allow you to refund.
This is a corruption or incorrect setting Paypal's side. You engineering department don't want to know either.
It makes you feel like Paypal don't trust us anymore. It's a shame after 20 years of being a customer. We have stopped using Paypal for receiving payments as embarising, so use Stripe instead now until they resolve.
