How to correctly authorise paypal credit card payment in RESTful integration?

[nickornotto1]

I am doing RESTful integration of PayPal in C#

I am trying to create a payment with `credit card` as a `payment_method`.

So far I have the angular config and am successfully creating and get authorization response with state "authorized" in my api `Create` method:

    createdPayment = payment.Create(apiContext);
    
    return createdPayment;

and then:

    Authorization authorization = payment.transactions[0].related_resources[0].authorization;

the `authorization` state is authorized.

but I'm getting the response in console:

    ppxo_no_token_passed_to_payment
    Object { timestamp: 1531389390897, windowID: "8b6e6d498f", pageID: "60540ae7ab", prev_corr_ids: "", referer: "localhost:63109", host: "localhost:63109", path: "/order", env: "production", country: "US", lang: "en", … }

(btw not sure it says `env: production` if I'm using the sandbox?)

and:

    No value passed to payment

And when I click the confirmation link from payment object (which is eg. https://api.sandbox.paypal.com/v1/payments/payment/PAY-6RD0371739881292ULNDSPRA) I'm getting json:
    

    name    "AUTHENTICATION_FAILURE"
    message    "Authentication failed due to invalid authentication credentials or a missing Authorization header."
    links    
    0    
    href    "https://developer.paypal.com/docs/api/overview/#error"
    rel    "information_link"

So the payment effectively failed.

I went to the provided ref link: https://developer.paypal.com/docs/api/overview/#error and found out that Access token-related issues often cause authentication errors but I'm getting a Bearer token after successfully creating the payment.

The question is what I'm supposed to do with the Bearer token if anything? what to return in my `payment` method in button config? what to pass to config's `onAuthorize` method if anything? And how to authorise the payment successfully?

I tried to look for solution through paypal api and didn't find anything to answer my question so far.

My angular config:

    paypalConfig = {
        env: 'sandbox',
        client: {
            sandbox: 'my sandbox key'
        },
        commit: true,
        payment: (data: any, actions: any) => {
            // 2. Make a request to your server
            var url = '/paypal/create/';

            return actions.request.post(url)
                .then(function (res: any) {
                        // What HERE?
                        return res.id; // if I return payment id then I get redirected to paypal.com where it obviously says the transation is invalid because I'm doing the process in sandbox not live env
                });
        },
        onAuthorize: (data: any, actions: any) => {
            // WHAT HERE??
            // normally I'd do a request to paypal with paymentid and payerid (https://developer.paypal.com/docs/checkout/how-to/server-integration/#1-set-up-your-client-to-call-your-server) but in case of credit_card payment I don't get those
        }
    };

My `Create` method is based on the `CreatePayment` provided here - the only difference is that I use `payment_method = "credit_card"` (instead of paypal) and I return `Payment` object back to angular instead of redirecting to approval url.

Btw `onAuthorize` method is required by button config. Normally with paypal funds I would send `paymentId` and `payerId` back to paypal for authorising the payment but in case of credit card method I get the payment already authorised within `payment` function. The only problem is it fails.