error when validate sender status is false 

there is a problem when the call to  obtain the status of a sender return false, the callback for the promise is never reached because the errorCase function is throwing an exception that never is catched

with my changes now no matter the result of the status, the respond is always reached 

function to validate the new changes propossed
++++++++++++++++
function isAvalidSender(email) {

  var result = dyn.senders.status(email).then(function(x) {
    console.log('CALLBACK!!!');

    console.log('response %s', JSON.stringify(x));

    if (x) {
      return true;

    }

    return false;

  });

}