To troubleshoot problems with events in Microsoft Calendar, please follow these steps:

1. Check the Upcoming Events section and ensure it contains all current events.
2. Verify that your calendar on the web shows the updated events.
3. Review the calendar syncing setup on all devices.
4. Try disabling and re-enabling calendar syncing on each device.
5. Ensure you're using the latest version of the Microsoft Calendar app.
6. Disable third-party calendar services for further troubleshooting.