Please try to check the issue with the following guide:
- Go to TickTick Settings > Sounds & Notifications, make sure that reminders are ON.
- Make sure Google Play Services is installed on your phone.
- Check notification priority for TickTick in Android settings, it can be called Importance or Behavior depending on your device.
- If your phone uses some battery saving software, make sure that TickTick is whitelisted in that application.
What if the issue still exists after I try the above tips?
Please send us feedback within the TickTick app. To send us feedback from Android phone, here is the path: Settings > Feedback & Suggestions.