When a guest tries to do an order they get the following message:
PayPal gateway has rejected request. Payment has already been made for this InvoiceID (#10412: Duplicate invoice).
As far as I can tell this doesn't happen for people that made an account. I know this because I tried as a guest and as an account. Is there a way to fix this? I am on Magento 1.9.3.2 and this just starting happening today/yesterday. Not 100% sure of the actual time.