Magento 2 - PayPal Express Checkout duplicate invoice id

Question

When I checkout using PayPal express checkout, it returns an error message

PayPal gateway has rejected request. Payment has already been made for this InvoiceID (#10412: Duplicate invoice)

I have tried to reset everything but still get the same error.

How to solve this issue?

Answer 1

It is because the same Invoice ID has been submitted to the same PayPal business account. This always happens on dev server as the Invoice ID always reset due to re-installation.

Workaround - Allow Duplicate Invoice

Profile > Payment Receiving Preferences

Block accidental payments > allow multiple payments per invoice ID

Answer 2

Updating in Feb '21 PayPal account > Settings (right top gear symbol) > Seller tools (last option on menu) > scroll down to Payment Preferences > Block Accidental Payments