Hi,
Some notifications are local others are from OSM servers.
In order to get any notification you need to allow them. To allow them for fist time you need to start a 'local' notification like stadium building, training, data analyst....
After enable notifications you'll get ALL server notifications (transfers, match simulations....)
To get local notifications, trainings/stadium improvements... completed, you have to start them locally also. If you start them on Web version or on a different device you won't get notifications.
I'm assuming that you started notifications on a different device and that's the reason why you didn't got it. Ifit wasn't the case and the problem persiss, please report it again with a clear description of the steps you did.