400 status code error

If you are got http response code 400 when accessing https //api.sandbox.paypal.com/v1/payments/payment

#1 Regular Price is required

Make sure that Listing Plans -> Your Plan -> The Regular Price is not empty

#2 If you are using the Recurring Payment Method, make sure that your Listing Plan (Listing Plans -> Your Plan) -> Period Day is not empty

403 status code

If you face the following issue: http response code 403 when accessing https://api.sandbox.paypal.com/v1/payments/billing-plans/.

Please follow these steps to resolve it:

1. Go to https://developer.paypal.com/
2. Log into your site account
3. From the Dashboard sidebar, click on My Apps & Credentials
4. Scroll down to REST API apps, Click on your App
5. If you are using Live mode, please switch on Live area
6. Scroll down to LIVE APP SETTINGS / SANDBOX APP SETTINGS
7. Check on: Accept payments, Invoicing