Everything works in Sandbox, but I get IdentityException using PayPal Live

Question

I am integrating PayPal payments into my website using the PayPal REST API using the .NET SDK ( https://www.nuget.org/packages/PayPal ). My website is running as an App Service in Microsoft Azure. I have a testing slot configured to use PayPal Sandbox, and a production slot which uses the Live credentials (configuration settings are in the App Settings, and are slot-specific).

Everything works fine in Sandbox, and I am able to authenticate and get an access token using the live configuration, but when I try to process anything I get a PayPal.IdentityException (I tried Payments as well as Billing Plans and Agreements). If I look at the IdentityException Response (or Details ), I get this:

{"error":"invalid_token","error_description":"The token passed in was not found in the system"}

Digging further, it seems that the ApiContext that is created has the AccessToken set, but the Config property is null . If I look at the API request (from PayPalResource.LastRequestDetails.Value ) I see that even though it's using the live configuration, it's sending the request to api.sandbox.paypal.com, not the live API. This seems to be a problem with my ApiContext , which I establish as follows:

public static APIContext Authenticate()
{
    string clientId = ConfigurationManager.AppSettings["PayPalClientId"];
    string clientSecret = ConfigurationManager.AppSettings["PayPalSecret"];
    string mode = ConfigurationManager.AppSettings["PayPalMode"];

    var config = new Dictionary<string, string>();
    config.Add("mode", mode);
    config.Add("clientId", clientId);
    config.Add("clientSecret", clientSecret);

    accessToken = new OAuthTokenCredential(config).GetAccessToken();
    return new APIContext(accessToken);    // <--- problem here
}

Apart from manually constructing the Config dictionary rather than using the ConfigManager to create it automatically from a custom config section, this follows the .NET SDK documentation very closely. What am I doing wrong?

Answer 1

The problem here is that all that is passed to the APIContext constructor is the accessToken . Without having the settings in the custom config section of Web.config or App.config , APIContext defaults to using the sandbox API.

The solution is to explicitly set the Config property using an Object Initializer:

return new APIContext(accessToken) { Config = config };    // <---- fixed