If you don't receive event notifications, please check the following.
1. Check your device's notification settings
Open your device's "Settings" app → "Notifications" and make sure notifications from Smart Planner are allowed (you can also check this in "Settings" → "Apps" → "Smart Planner" → "Notifications").
Smart Planner has several notification types: "Event reminders", "Daily summary", "Todo reminders", and "Diary reminders". Please make sure each of them is turned on as well.
2. Check the "Alarms & reminders" permission
To notify you exactly at the time you set, the app needs the "Alarms & reminders" permission. Open your device's "Settings" app → "Apps" → "Smart Planner" → "Alarms & reminders" and allow this permission if it is not allowed.
3. Check Do Not Disturb and power-saving settings
Notifications don't arrive while your device is in "Do Not Disturb". Also, if power-saving settings (such as Battery Saver) restrict Smart Planner from running in the background, notifications may be delayed or not arrive at all. The names and locations of these items differ depending on your device, so please check your device's "Settings" app.
4. Check that the event has a notification set
Open the event's editing screen and make sure an "Alert" is set. If you want every new event to get a notification automatically, set "Timed Notifications" and "All-Day Notifications" (Default Notification Settings) in the settings screen under "Calendar Settings" → "Reminder Settings".
※ For Google Calendar events, notifications may also come from the Google Calendar app.