title: there was a issue communicating with paypal servers
body: <p>I am integrating  paypal SDK in IOS App and I just download the sdk from GITHUB and Tired to run on simulator. every thing is fine for PaypalNo Environment Mode but If changed to Paypal Sandbox mode it's not working even through I created Paypal Account and created Sandbox Account and given Correct Paypal Sandbox Client ID.</p>
  
  <p>I am Getting an  error:</p>
  
  <pre><code>PayPal SDK: Request has failed with error: pp_service_error_json_parse_error - System error. Please try again later. (500) | PayPal Debug-ID: 5635514483a49 [sandbox, PayPal iOS SDK 2.1.1] | Details: (
          {
          "ns_error" = "Error Domain=NSCocoaErrorDomain Code=3840 \"The operation couldn\U2019t be completed. (Cocoa error 3840.)\" (No value.) UserInfo=0xba4a7c0 {NSDebugDescription=No value.}";
      }
  ).
  </code></pre>