1. Login to PayPal Merchant account.
2. Click Profile > My Selling Tools > click the Update link beside API Access
3. Grant API Permission > clicked API Permissions and use ppexpresscheckout_api1.netsuite.com as the third party API username and add the following:
- Use Express Checkout to process payments
- Issue a refund for a specific transaction
- Obtain information about a single transaction
- Search your transactions for items that match specific criteria and display the results.
- Authorize and capture your PayPal transactions.
4. Navigate back to Setup > Accounting > PayPal Accounts check the Use Express Checkout and save.