How can I gain access to the payment API endpoints?

You may have access to the API but having trouble accessing the payment API endpoints. When creating an API token, you must set the token permissions to read and write access for Payments in order to have access to these endpoints. Reference the payment API documentation for any read or write restrictions that may apply to your e-commerce platform. 

Depending on your permission settings, you may require the Store Owner to make these updates for you directly.