Using Samsung Galaxy Note 5. I am unable to preview the text message sender or beginning of their message. This change happened all of a sudden and the notification settings are correct. When I receive a text message I receive a notification saying "Messages" and underneath that "New Message" but I have to open the application in order to see who it's even from.
DId anything change like you sync'd work email or something like that? Some rules from companies will block things like this. You can maybe boot your device in safe mode and still see if it is doing the same thing.