Braintree doc: https://developer.paypal.com/braintree/docs/guides/paypal/testing-go-live#linked-paypal-testing
You have to link your Paypal account to Braintree
In order to link a PayPal sandbox test account to your Braintree sandbox account, you will need the API credentials for that PayPal sandbox test account.
If you don't already have a PayPal sandbox test account for testing your Braintree integration, create a new one by following these steps:
Create a PayPal business sandbox account:
- Log into the PayPal Developer Dashboard
- Navigate to Sandbox > Accounts
- Click Create Account
- Select the same Country as your Braintree sandbox account
- Select the account type as Business
Go to the Create New App page
- Create an app to get sandbox API credentials
- Select the same sandbox developer account as the test account created in step 1
Note the following Sandbox API Credentials for the new app you created:
- Email address associated with this app
- Client ID
- Secret
Once you have those PayPal sandbox API credentials, enter them in your Braintree sandbox:
- Log into your Braintree sandbox Control Panel
- Navigate to Settings > Processing > Payment Methods > PayPal
- Click Link Sandbox
- Enter the Email address, Client ID, and Client Secret for your PayPal sandbox test account
- Click Link PayPal Sandbox