Paypal Disputes Sandbox Testing

i was trying to tests paypal disputes in a sandbox and was following this guide: https://developer.paypal.com/docs/integration/direct/customer-disputes/integration-guide/#sandbox-only-methods.

However, on the step 2(Get permission from the buyer) the code provided by paypal for connect button generation was throwing js syntax error, so I changed it to this:

<span id='cwppButton'></span>
<script src="https://www.paypalobjects.com/js/external/connect/api.js"></script>
<script>
        paypal.use( ['login'], function (login) {
                login.render ({
                        "appid": "MY_CLIENT_ID",
                        "authend": "sandbox",
                        "scopes": "openid",
                        "containerid": "cwppButton",
                        "locale": "en-us",
                        "buttonType": "CWP",
                        "buttonSize": "lg",
                        "returnurl": "https://a62add0d.ngrok.io/api/payments/paypal/get-token/"
                });
          });
</script>

How u can see i changed scopes to just "openid", cuz separating links provided by paypal in this example gave me "Invalid Scope" error However i got access token from the button in this step. The next problem i faced was on step 4 (Generate JSON web token for PayPal Authorization Assertion), the code paypal provided gave syntax error, so i replaced it to this:

<span id='cwppButton'></span>
<html>
<script>
            function base64url(source) {
                    encodedSource = btoa(source);
                    encodedSource = encodedSource.replace(/=+$/, '"');
                    encodedSource = encodedSource.replace(/\+/g, '-');
                    encodedSource = encodedSource.replace(/\//g, '-');

                    return encodedSource;
            }
            function generateJWT() {
                    var header = {"alg": "none", "typ": "JWT"};
                    var data = {"iss"   :"MY_CLIENT_ID",
                               "email" : "casino.player@gmail.com" };
                    document.write(base64url(JSON.stringify(header)) + "." +
                    base64url(JSON.stringify(data)) + ".");
            }
</script>
<body onload="generateJWT()"/>

And as a result running create dispute request on step 6 i've got this error:

{
    "error": "invalid_request",
    "error_description": "No permissions to set target_client_id"
}

My question is how to setup and test correctly paypal disputes in sandbox? If somebody was facing the same problem with disputes testing?

Solution

From Step 1 https://developer.paypal.com/docs/integration/direct/customer-disputes/integration-guide/#sandbox-only-methods :

Set up your REST app with the following scope:

https://uri.paypal.com/services/disputes/create = DISPUTE_CREATE

Have you done this? This first step may need to be done for your sandbox account / sandbox client ID REST APP by PayPal, as you are integrating an API that requires approval.

Then, you will be able to complete Step 2 with the necessary scope.

Without that required scope and permission, you will get that error in Step 4.