Transaction Invalid
If you are getting a “Transaction is invalid” error, there is an issue with your PayPal account. Fortunately, it is easy to address
This is a short checklist of things to go over in your PayPal account to get rid of this pesky error
1) Ensure your PayPal account is verified.
You should see the above when you go to this URL. If not, just follow the steps here to get verified.
2) Ensure you’ve confirmed your email address with PayPal.
If you see “Unconfirmed” next to your email address like the above screenshot, select it and click “Confirm”
3) Did you enable your PayPal account for the right currency?
Make sure you are accepting the same currency on your Donate App as your settings (above) indicate in PayPal.