Appears to process correctly, but transactions never complete

A client has come to us with quite an odd issue with this plugin; transactions appear to process correctly, but customers aren’t actually charged, and no record shows up in either the clients Paypal account, or the customers. It does, however, put a hold on the card used to process the payment, but the hold is automatically released after some time as the transaction never completes.

Some things I’ve checked:

– In Paypal, under “Live API call history,” all listings are marked with a green checkmark, and a 200 or 2001 status code.
– In Paypal, under “Live webhook events,” everything has a green checkmark, including the specific transaction I’m testing, which does contain all the submitted data (as best as I can tell)
– We are using live credentials, are they are correct.
– In WordPress, Under WooCommerce -> Status -> Logs, I see a log for the specific transaction I’m testing, and everything is listed as “200 OK” or “201 Created.”
– In Paypal, as the business, the transaction doesn’t appear.
– In Payal, as the customer, the transaction doesn’t appear.
– As a customer, in my online banking, I see the hold for the appropriate funds as a pending transaction, but this will automatically be released after a few days.

I suspect something to do with some sort of handshake is failing; it clearly is processing *most* of the hooks, it’s just the final bit that finalizes the transaction that isn’t working.

Is this something you’ve seen before? Can you point us in the right direction?

The page I need help with: [log in to see the link]