I keep getting a “Request failed with response code 401” when trying to push via Parse.cloudCode

Follow

I have double, triple, and quadruple checked that I have the right master key that I'm passing. My parameters are taking directly from the UA website also so it can't be that. What I'm doing wrong here???

Parse.Cloud.define("sendPush", function(request, response) {

  var Buffer = require('buffer').Buffer;

  var parameters = {
    "audience" : "all",
     "device_types" : "all",
     "notification" : {
         "alert" : "Hello from Urban Airship."
     }
  };

  var params = JSON.stringify(parameters);

  Parse.Cloud.httpRequest({
    url: "https://go.urbanairship.com/api/push/",
    method: 'POST',
    headers: {
        "Content-Type" : "application/json",
        "Authorization" : 'Basic ' + new Buffer('MASTER_KEY').toString('base64'),
        "Accept" : "application/vnd.urbanairship+json; version=3;"
    },
    body: params,
    success: function(httpResponse) {
        response.error(httpResponse);
    },
    error: function(httpResponse) {
      response.error('Request failed with response code ' + httpResponse.status);
    }
  });

});

I have also tried:

"Authorization" : 'Basic ' + new Buffer('APP_SECRET:MASTER_KEY').toString('base64'),