When using PayPal's Sandbox what login do I use when it asks me to log in?

I'm developing an application that is trying to use Paypal's Express Checkout. After I SetExpressCheckout and "Success" is returned I开发者_高级运维 redirect to PayPal's Sandbox site with this URL: return Redirect("http://www.sandbox.paypal.com?cmd=_express-checkout&TOKEN=" + viewModel.Last()["TOKEN"]);

When I run this from localhost, PayPal says that I need to log in. Now I have a Sandbox login, but I believe I have a Seller test account as well. I think I also need a buyer test account, But whenever I click "New Test Account: Preconfigured" and enter info for a "Buyer" account, it submits but I don't see the new test account anywhere.

So,

A: what login am I supposed to use?

B: where am I supposed to login?

thanks for any help

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btw: I know that my initial call to the api is successful:

TOKEN: EC-8EB417855U0122113

TIMESTAMP: 2011-05-20T19:42:41Z

CORRELATIONID: 3b01e2f4ae858

ACK: Success

VERSION: 51.0

BUILD: 1882144

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When you're testing the ExpressCheckout functionality, you need to be logged in with your Sandbox account. The reason is that PayPal needs to be able to figure out which Sandbox account to associate the Checkout with.