警报管理器在API 23之后未按预期启动服务

Recently i have upgraded my project to 26 Api level. after that alarm manager is not working for me. I don't know what's the problem but i guess the alarm is not at all working, whenever app is in background for all device above lolipop(>=M). i have gone through other questions and and have followed some suggestion like 'WakefulBroadcastReceiver', Recently i have upgraded my project to 26 Api l