This is a trivial post but Paypal integration has been a headache over the past few years which the manuals having incorrect information, differences between the UK and US apis and hugely unhelpful error codes. Things have gotten a bit better in recent times but still not as good as it should be given the proliferation of Paypal integration. We recently had a little issue that had me banging my head against my keyboard. Now this IS in the api specification but I think this is a bit absurd.
Apparently, you need to specify the amount as a decimal number to two decimal places otherwise the amount is flagged as invalid. So you must give your amount value as xx.xx and not xx.xxx or any other number of decimal places. You will receive an INVALID AMOUNT error and the transaction history in Paypal Manager will show INVALID AMOUNT $0.00 USD, even if you are using another currency.
