title: PayPal RESTFul Execute billing agreement return invalid token
body: <p>I am trying to test RESTFul API for creating subscription in my sandbox account.</p>
  
  <p>1- I have created BillingPlan and made it active. 
  2- create a billing agreement, and I got approval_url back.
  3- the customer goes to approval_url (customer in this case one of my other test accounts in sand box). the user logs in and approve the billing agreement. PayPal redirect the customer to my redirect url
  4- I then tried to execute the agreement and I get "invalid token" error which is weird as it is teh token given by PayPal.</p>
  
  <p>here is the code snippet I use to execute teh agreement, "billingAgreementToken" is token returned by PayPal when creating the agreement, and it is the same token used when paypal redirect the user back to my site.</p>
  
  <pre><code>    APIContext apiContext = new APIContext(accessToken);
  
      Agreement agreement = new Agreement();
      agreement.setToken(billingAgreementToken);
      System.out.println("Agreement " + agreement);
  
  
     Agreement executedAgreement = agreement.execute(apiContext);
  </code></pre>
  
  <p>any idea why I am getting "invalid token" error ?</p>
  
  <p>adding the response I am getting after calling execute:</p>
  
  <p>SEVERE: Error code : 400 with response : {"name":"BUSINESS_VALIDATION_ERROR","details":[{"field":"validation_failure","issue":"Invalid Payment Token."}],"message":"Validation Error.","information_link":"<a href="https://developer.paypal.com/webapps/developer/docs/api/#BUSINESS_VALIDATION_ERROR" rel="nofollow">https://developer.paypal.com/webapps/developer/docs/api/#BUSINESS_VALIDATION_ERROR</a>","debug_id":"e2e2b7b0ff696"}
  error com.paypal.core.rest.PayPalRESTException: Error code : 400 with response : {"name":"BUSINESS_VALIDATION_ERROR","details":[{"field":"validation_failure","issue":"Invalid Payment Token."}],"message":"Validation Error.","information_link":"<a href="https://developer.paypal.com/webapps/developer/docs/api/#BUSINESS_VALIDATION_ERROR" rel="nofollow">https://developer.paypal.com/webapps/developer/docs/api/#BUSINESS_VALIDATION_ERROR</a>","debug_id":"e2e2b7b0ff696"}</p>