Hello I'm using https://www.evoluted.net/thinktank/web-development/paypal-php-integration so my customers can upgrade their accounts directly through my website. My mistake was that the transactions were being made as physical goods, and now PayPal is requiring proof of fulfillment.
If anyone knows how I would change that PHP example to be for Digital Goods, I would sincerely appreciate it.
In your request body, set application_context to an object with a shipping_preference of NO_SHIPPING