Why is my phone no longer displaying email/message tile updates

[WPCentral Question]

I have made no changes to my notification settings and have notifications turned on for email and text messages, but my phone no longer seems to register that I am receiving emails and text messages. The tiles don't update and there is nothing in the action center. When I launch the app (e.g. email), I can tell that there are new items.

The action center and phone tile do show if I've missed a call.

I have a Lumia 640 with T-Mobile.