I am not receiving text notifications when my iPhone is unlocked.

Out of the blue, I stopped receiving my text message notifications on my iPhone 6 when the phone is unlocked. I double checked my settings and they are just as they should be (settings, notifications, messages, alert style to banner). However the banners don't pop up anymore. If I am using my phone I have to go back and check for a little red bubble for a text. Any suggestions?