Authentication with p12 key give error User cannot access account

Question

I have a MVC web-application that update the products on the eCommerce site. Now we enrolled into the google merchant center and my objective is to update the products at the same time. I am using the Google.Apis.ShoppingContent.v2_1 API.

This is my API Credentials

This is my API service account

I have used the google account email address for the user as well as the service account email but with the same result.

I have the following

    static string[] Scopes = { ShoppingContentService.Scope.Content};
    static string P12Secret =  @"~\Content\XXXXXX-5cab03fb904a.p12";
    static string userName = "[email protected]";

    static public async Task RunTest2()
        {
            var certificate = new X509Certificate2(P12Secret, "notasecret", X509KeyStorageFlags.MachineKeySet | X509KeyStorageFlags.Exportable);
            var credential = new ServiceAccountCredential(new ServiceAccountCredential.Initializer(userName)
            {
                Scopes = Scopes
            }.FromCertificate(certificate));

            var service = new ShoppingContentService(new BaseClientService.Initializer
            {
                ApplicationName = ApplicationName,
                HttpClientInitializer = credential
            });

            try
            {
                var result = await service.Products.List("My MerchantID").ExecuteAsync();
            }
            catch (Exception e)
            {
                Console.WriteLine(e.Message);
            }
        }

When I execute var result = await service.Products.List("My MerchantID").ExecuteAsync(); I get the error

e.Message = "Google.Apis.Requests.RequestError\nUser cannot access account 123456789 [401]\r\nErrors [\r\n\tMessage[User cannot access account 123456789 ] Location[ - ] Reason[auth/account_access_denied] Domain[content.ContentErrorDomain]\r\n]\r\n"

Answer 1

Documentaiton

Service accounts are special Google accounts that can be used by applications to access Google APIs programmatically via OAuth 2.0. A service account uses an OAuth 2.0 flow that does not require human authorization. Instead, it uses a key file that only your application can access. This guide discusses how to access the Content API for Shopping with service accounts.

Service accounts need to be pre authorized. If its not then it doesnt have access to any data.

User cannot access account 123456789

Means that it does not have access you have forgotten to grant it access. Check the Documentaiton look for the section below follow all of the steps.