Why aren't notifications from messages showing up on the lock screen?

[AC Question]

Notification from messages not showing up on lock screen!!!!

Ok so i just got a Galaxy s6 the other day and when i receive text messages i dont get notified on the lock screen. I've read all the other threads about this and done what has been told nothing works. When i restart my device I get a lock screen notification from my unread message I had before i restarted it, but if i get a message again it doesnt show up.