I have had this problem for months now. I have several Apple devices. Some older some new. Currently I have and use a 2014 MAC Mini, a iPad Air 2, iPhone 4s (WiFi only for music,) Watch 3, Watch 4, iPad 12.9 (2nd Gen,) iPad 10.5, and just bought an iPhone 12. I had a iPhone 7 which had the same problem of no notifications. I upgraded partly hoping the newer iPhone would solve this issue. It did not. I use the iPhone 12 and the Watch 4 as daily devices. The watch is paired with the iPhone as it should be. When I receive an iMessage or a SMS, or an email, the phone does nothing, no sounds, no Lock Screen notification, The phone is not muted, and the volume is up. The phone has been setup to provide audible and visual notifications. The Watch 4, or the Watch 3 are up to date, and setup the same way. With the Watch 4 and iPhone 12 if a message comes in, again the phone does nothing, the watch DOES NOT make a sound, but DOES give me a small tick with haptics. But nothing on its screen unless I manually wake it. I get the same thing with a received email. Curious when I receive a phone call, it all works as expected, the iPhone 12 sounds my ringtone, the Watch 4 dingles its ring sound and I get normal haptic vibration, and the watch shows me who’s calling. So phone calls work, nothing else does. If I have my iPhone unlocked, it will play the message sound and show a banner. If I lock the phone and I receive a message, nothing happens. After reading some advice on a forum, to turn off Bluetooth, the phone will work like it should with messages and emails. This is an unacceptable workaround as it defeats the main purpose of the Watch 4. This is clearly a software bug, as it has persisted through various iOS updates, and in my case going from iPhone 7 to a iPhone 12. The behavior between iPhone and Watch when paired has to be right or I will just sell both Watch’s and go back to FitBit or some other watch device. Pairing the Watch 4 with the health app is the main reason I paid up for an Apple Watch instead of a much cheaper device. Help!