The Moto E4 Plus does not have a notification LED like your old phone did. Instead, Motorola flashes the time and recent notifications on the screen briefly when the phone is moved or if the phone senses nearby movement. There is an app on your phone called Moto that lets you configure how this and other things on your phone work.
Some people like this feature and others prefer the flashing notification LED.
If you would prefer a flashing notification LED, the workaround is to use an app that will use the camera flash in lieu of the notification LED. You can find many free apps in the Play store that you can try. Here is a link to one to get you started: