How to solve
iOS/Android
Check if the calendar is selected in "All Calendars"
- Tap the image icon in the upper left corner
- Tap the "All Calendars" tab below your profile details
- Tap "Settings" in the bottom right corner
- Check if the calendar you want to display is selected
- iOS widgets cannot display external calendar events
Restart your device
- Delete the widget
- Restart the device
- Add the widget again
iOS17
Set Calendar Permissions to Full Access
- Select Settings → TimeTree → Calendar → Full Access for the device itself