Subscription not working in dev sandbox

I have the following code to subscribe agent presence. Base on RingCentral API document, it should get notifed when there's incoming call. But I can only get notified when agent changes presence. But when there's incoming call, no notification.

var loadAgentInfo = function (allAgents) {

var agentIds = getAgentIds(allAgents);

if (agentIds) {

$scope.rcsdk.platform().get('/account/~/extension/' + agentIds, {}).then(function(agentRes) {

var agents = agentRes.multipart();

var subscription = $scope.rcsdk.createSubscription();

var callLogSubscription = $scope.rcsdk.createSubscription();

subscription.on(subscription.events.notification, function(msg) {

$scope.loadAgentsStatus();

});

var callLogEvents = [];

var presenceEvents = [];

for (var j = 0; j < agents.length; j++) {

var agentJson = agents[j].json();

populateAgentInfo(agentJson);

//presenceEvents.push('/account/~/extension/'+ agentJson.id + '/presence');

presenceEvents.push('/account/~/extension/'+ agentJson.id + '/presence?detailedTelephonyState=true');

}

presenceEvents.push('/account/~/presence');

subscription.setEventFilters(presenceEvents).register();

$scope.$apply();

$scope.loadAgentsStatus();

}).catch(function(agentErr) {

Notification.error({message: "Loading agent info failed!", positionY: 'top', positionX: 'center', delay: 10 * 1000});

});

}

}