Problem in integrating Paypal to accept payments in USD
I have got my payment system custom developed in PHP for my website https://asthaclinic.com. The code seems to work well with the sandbox mode but it gives error with USD currency. However, if INR is defined as the currency, it works alright. Have I missed something? Will I need to do something else for development mode apart from changing merchant credentials and mode?
I am a Business individual from India and want to accept payments in USD from my international customers. I already have another payment gateway integrated for my domestic customers. For reference, here is the link to payment system: