Here are some steps you can take to troubleshoot why the Microsoft calendar is not displaying meeting details for events:
Make sure you have all the necessary settings in place (i.e turn on/off notifications, change the calendar view, etc).
Check if your app has been updated recently (both for your device and for the Microsoft calendar).
Restart the app or device.
Make sure there is an active internet connection.
Check if the calendar is set to the correct time and date.
Sign out and then sign back in to the account.
Contact support if the issue cannot be resolved on your own.