Paypal Oauth return server error getting token in sample PizzaApp -

I'm trying to get an example of a pizza app for PayPal Rest API and I get an error from the server Receiving 500 responses

The error appears during the first call to receive the atken token.

  Get personal string accessibility {{string tokenAccess = new OAuthToken credentials (Client ID, Client Secret) .GetAccessToken (); Return tokenAccess; }}   
 is used that the client and the secret web .config have my own sandbox cred I have not modified this sample app in any way, except for the credit.  
 In addition, I am using the correct end point,  
  & lt; Add name = "endpoint" value = "https://api.sandbox.paypal.com" />   
 Does anyone offer some tips to reduce the problem?  
 Log: 2013-06-21 10: 25: 20797 [7792] Debug PayPal. OathToken credential [(empty)] grant_type = client IDARAnalial 2013-06-21 10:25:25 22,622 [7792] Information PayPal OAuthTokenCredential [(empty)] Internal SecureAir response received from server 2013-06-21 10: 25: 22,622 [ 7792] error paypal. Exhibit PayPalException [(empty)] Remote server returned an error: (500) Internal server error PayPal.Exception.PayPalException: Remote server sent an error: (500) Internal server error --- & gt; System.Net.WebException: Remote server returned an error: (500) Internal Server Error on System.Net.HttpWebRequest.GetResponse () on PayPal.OAuthTokenCredential.GenerateOAuthToken (String base64ClientID) - End of Internal Exception Stack Trace --- < / P>  
 
 
 I'm not sure how our standard release announcement slipped - we will ensure that all the changes (they are already in the future) Are documented in the change log) are also announced so that everyone will know that when a SDK is a new release and a bug has been fixed