IPhone 6 plus blinks but no message or notification?

I recently got an iphone and everything is good but sometimes my iphone it blinks, turns on and make that sound. The same sound it makes when i get a text message, but there's nothing in the notification area. I know its not email. Email just do a quick vibrate so what is this?

Go to your settings under notifications and click "messages" at the very bottom there should be an "repeat alert" option - click on it and select "never". That should keep it from happening again

Go to Settings, tap on General, Tap on Accessibility, Toggle LED Flash for Alerts to Off. For advance security of your smart phone you must install Leo Privacy Guard, PERFECT PRIVACY.