You can check your NiceDay notification settings. Check both the app (tap on the cogwheel on your profile page) and your phone’s settings:
- Apple: Settings > Notifications > NiceDay > Allow Notifications
- Android: Settings > Apps & Notifications > Notifications > Recently Sent > NiceDay
Ensure that your notifications are turned on. If the notifications are already turned on, you can try turning them off and on again. This often solves problems with notifications.