Payment Processing Returns a 404 Error

[Legacy47]

We are trying to connect 3rd party Ring Central to our stores to process payments (CC transactions) through Shopify via the API.  We have reviewed the API library and have been able to confirm the auth and enter a credit card into the vault, but processing consistently returns a 404 error.  Can we connect via the API, or do we need to use/develop a Sales Channel for Ring Central?