Push notification from Laravel using google firebase

I am trying to send push notification using google firebase . Notification not coming to phone

public function pushNotificationToUsersTest(){ 
         $apikey = env('FCM_SERVER_KEY');
        $deviceToken = array("deviceTocken_1,deviceTocken_2");
		$url = 'https://fcm.googleapis.com/fcm/send';
    	$message = "Message from server";	 

        foreach ($deviceToken as $key => $Token) {
            $preview_message = "ACTIONABLE";
            $sound = "default";

    		$fields = array(
    			'to'  => $Token,
    			'data' => array( 
    				'message' => $message,
    				'notification_type' => "message_type",
    				'message_content' => "message_content",
    				'chat_type' => "chat_type",
    				'badge' => 10,
    				'category' => $preview_message,
    				'sound' => $sound,
    				)
    			);
    			
    			//header with content_type api key
    			$headers = array(
    				'Content-Type:application/json',
    				'Authorization:key='.$apikey
    			);
    			
    			$ch = curl_init();
    			curl_setopt($ch, CURLOPT_URL, $url);
    			curl_setopt($ch, CURLOPT_POST, true);
    			curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
    			curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    			curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
    			curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
    			curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($fields));
    			$result = curl_exec($ch);

    			curl_close($ch);
            }
             print_r($result);
}

On print result I am getting like this

{"multicast_id":1610930223174111380,"success":1,"failure":0,"canonical_ids":0,"results":[{"message_id":"0:1657873770379569%73be5013f9fd7ecd"}]}1

When I checked respose code

$httpcode = curl_getinfo($ch, CURLINFO_HTTP_CODE);

It gives output 400. Don't know what the issue