[Plugin: Woocommerce] Error 10413 on checkout

I’ve been using a personal paypal account for all payments on my site up until recently. It was problematic as orders would be stuck in “on hold”, or just outright cancelled, even though the money had gone into the paypal account.

It appeared to be an IPN issue, but making the necessary changes did not help and subsequently I lost hundreds of £s worth of orders. I have since changed to a business paypal account and this problem seems to have gone for now.

However, I’ve received an email from a customer stating 10413 error on checkout. I believe this pertains to amounts not adding up. We have numerous coupon codes and having trawled the internet I believe this may be a culprit. I did not see any indication of this error on IPN history or on the orders page so now I am worried that more people have had this problem. Getting desperate now as orders seem to be slowing down.

I had a freelancer do most of the website setup but he is not speedy in his responses and English is not his first language. Otherwise he did a good job.

I have no coding experience myself so I would like to ask if there is anything I can do myself to fix this?