If a customer receives a PayPal error in checkout saying "You do not have permissions to make this API call", it could be due to your Express Checkout being disabled in your PayPal settings. This means Tictail isn't able to communicate with your PayPal account. To enable Express Checkout, just follow the steps below.
1. Log in to your Paypal account and go to "Account settings" under "Profile".
2. Find "My selling tools" and click on "API access".
3. Then click "Enable Express Checkout".
4. Select "Accept Paypal payments before API permissions are set up" and click "Submit".
5. All done!