Unfortunately app stopped when FCM push notification run

ionic-v1
1

=> FCM push notification not working in above android version 5,
=> API create in php framework codeigniter,
=> When i try to send notification using FCM Unfortunately app stopped .
=> Please give me example to send FCM push notification using API.
below code ,

function send_android_notification($registration_ids, $message) {
$msg = array(‘message’ => $message,‘title’ => $message);
// $msg = array(‘message’ => $message,‘title’ => ‘heello’);
$fields = array(
‘registration_ids’ => array($registration_ids),
‘data’=> $msg
);

        $headers = array(
        'Authorization: key = AAAA4AEYLS8:APA91bFgkH-_IzUqh3GVRNsiEVdWzix84f4MXkAMpuTevMfz44EmAUSH2W1CvtKHiyW3gBFZCnJk2Cnd0mrqZ3N_bDF7yWn8tzzNkQaWF9rzKm2MJxIDMh9EjSaLxymgDz3fezeDOBCG', 
        'Content-Type: application/json'
        );
        // Open connection
        $ch = curl_init();

        // Set the url, number of POST vars, POST data
        curl_setopt( $ch,CURLOPT_URL, 'https://fcm.googleapis.com/fcm/send' );
        curl_setopt( $ch,CURLOPT_POST, true );
        curl_setopt( $ch,CURLOPT_HTTPHEADER, $headers );
        curl_setopt( $ch,CURLOPT_RETURNTRANSFER, true );

        // Disabling SSL Certificate support temporarly
        curl_setopt( $ch,CURLOPT_SSL_VERIFYPEER, false );
        curl_setopt( $ch,CURLOPT_POSTFIELDS, json_encode( $fields ) );

        // Execute post
        $result = curl_exec($ch);
        if($result === false){
        die('Curl failed:'.curl_errno($ch));
        }
        // Close connection
        curl_close( $ch );
        return $result;
        }

// call function
$result = $this->send_android_notification($android_device_token,$message);

Ionic Info

Cordova CLI: 7.0.0
Ionic Framework Version: 3.1.1
Ionic CLI Version: 2.2.3
Ionic App Lib Version: 2.2.1
Ionic App Scripts Version: 1.3.6
ios-deploy version: Not installed
ios-sim version: Not installed
OS: Windows 8.1
Node Version: v7.9.0
Xcode version: Not installed