I am using the following code to accept payments for digital goods:
https://www.x.com/blogs/Nate/2011/01/07/digital-goods-with-express-checkout-in-php
I have a sandbox account and I have used the API credentials from the sandbox account.
Everything works fine until I press the "Pay with PayPal" button. At this point when I try to login to continue the simulated transaction I receive the following error: "We are unable to complete your request at this time. Please try again later. We apologize for the inconvenience."
I have no idea whet I'm doing wrong, can somebody help?
There are a number of people on the X.com forums with the same issue. It appears to have been resolved for some of them by asking PayPal tech support to enable Digital Goods transactions for their sandbox account. Apparently this option is not available during normal sandbox setup.