Request dialog appears but request is not being sent - php

Question

I m trying to send app request using "apprequest" dialog
using following code
but in this the request dialog appears
but requests are not sent
var inviteFriends;
window.fbAsyncInit = function() {
FB.init({
appId : '112312312312321',
status : true,
channelUrl : '//mysite.com/include/fb/channel.php',
cookie : true,
frictionlessRequests : true
});
// Additional initialization code here
FB.getLoginStatus(function(response) {
if (response.status === 'connected') {
// the user is logged in and connected to your
// app, and response.authResponse supplies
// the user's ID, a valid access token, a signed
// request, and the time the access token
// and signed request each expire
console.log('authorized');
FB.api('/me', function(response) {
console.log(response.name);
});
inviteFriends=function(){
var l="";
FB.api('/me/friends',function(response){
console.warn(response.data.length);
for (var i=0; i<20;i++){
//alert(o.id);
l=l+','+response.data[i].id;
}
console.log(l);
FB.ui({method: 'apprequests',
message: 'Hey send me a pic usign picinchat.com in fb chat!',
to: l
}, function(response){
console.log(response.toSource());
});
}
});
}
inviteFriends();