I've added my Paypal account to Woocommerce, however payment from one of my customer failed.
I've contacted Paypal and they told me to my account was not registered. They advised me to add the Paypal API certificate (that I downloaded) into Woocommerce. However, there doesn't seem to be an option in Woocommerce to do so. Where can I add this certificate?
Thanks so much in advance!