title: Server unavailable error on calling Payment.Create in PayPal sdk
body: <p>I downloaded the Paypal SDK for C# and am trying to create a basic payment in my asp.net mvc app. I'm running the exact code mentioned in the paypal dev site, <a href="https://developer.paypal.com/webapps/developer/docs/api/#create-a-payment" rel="noreferrer">https://developer.paypal.com/webapps/developer/docs/api/#create-a-payment</a> but am getting an error (stack trace below). I'm able to get an access token so I'm assuming the app is able to communicate with the endpoint, but not sure why it complains in the Payment.create method. This is the first time I'm using asp.net mvc so am a little confused about what I could be doing wrong and would really appreciate any help :)</p>
  
  <p>My Web.config file has this section:</p>
  
  <pre><code>  &lt;paypal&gt;
      &lt;settings&gt;
        &lt;add name="endpoint" value="https://api.sandbox.paypal.com" /&gt;
        &lt;add name="connectionTimeout" value="360000" /&gt;
        &lt;add name="requestRetries" value="1" /&gt;
        &lt;add name="ClientID" value="xyz" /&gt;
        &lt;add name="ClientSecret" value="abc" /&gt;
      &lt;/settings&gt;
    &lt;/paypal&gt;
  </code></pre>
  
  <p>Stack trace:</p>
  
  <pre><code>PayPal.Exception.PayPalException was unhandled by user code   HResult=-2146233088   Message=Exception in HttpConnection Execute: Invalid HTTP response The remote server returned an error: (503) Server Unavailable.   Source=PayPalCoreSDK   StackTrace:
         at PayPal.PayPalResource.ConfigureAndExecute[T](Dictionary`2 config, IAPICallPreHandler apiCallPreHandler, HttpMethod httpMethod, String resourcePath)
         at PayPal.PayPalResource.ConfigureAndExecute[T](APIContext apiContext, HttpMethod httpMethod, String resource, String payload)
         at PayPal.Api.Payments.Payment.Create(APIContext apiContext)
         at PayPal.Api.Payments.Payment.Create(String accessToken)
         at Requext.Controllers.EventController.CreatePayment() in c:\Users\Ishan\Source\Repos\requext.com\Requext\Controllers\EventController.cs:line 169
         at Requext.Controllers.EventController.Test() in c:\Users\Ishan\Source\Repos\requext.com\Requext\Controllers\EventController.cs:line 95
         at lambda_method(Closure , ControllerBase , Object[] )
         at System.Web.Mvc.ActionMethodDispatcher.Execute(ControllerBase controller, Object[] parameters)
         at System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters)
         at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters)
         at System.Web.Mvc.Async.AsyncControllerActionInvoker.InvokeSynchronousActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters)
         at System.Web.Mvc.Async.AsyncControllerActionInvoker.&lt;&gt;c__DisplayClass42.&lt;BeginInvokeSynchronousActionMethod&gt;b__41()
         at System.Web.Mvc.Async.AsyncResultWrapper.&lt;&gt;c__DisplayClass8`1.&lt;BeginSynchronous&gt;b__7(IAsyncResult
  _)
         at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`1.End()
         at System.Web.Mvc.Async.AsyncResultWrapper.End[TResult](IAsyncResult asyncResult, Object tag)
         at System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult)
         at System.Web.Mvc.Async.AsyncControllerActionInvoker.&lt;&gt;c__DisplayClass37.&lt;&gt;c__DisplayClass39.&lt;BeginInvokeActionMethodWithFilters&gt;b__33()
         at System.Web.Mvc.Async.AsyncControllerActionInvoker.&lt;&gt;c__DisplayClass4f.&lt;InvokeActionMethodFilterAsynchronously&gt;b__49() InnerException: PayPal.Exception.ConnectionException
         HResult=-2146233088
         Message=Invalid HTTP response The remote server returned an error: (503) Server Unavailable.
         Source=PayPalCoreSDK
         Response=""
         StackTrace:
              at PayPal.HttpConnection.Execute(String payLoad, HttpWebRequest httpRequest)
         InnerException:
  </code></pre>