The calendar for Outlook has problems syncing to mobile devices. Sometimes, the default calendar app has problems syncing meetings/events from Office 365 Outlook to a phone, or someone else's meetings showing up on the phone's Outlook calendar. This usually happens when a GMU email is added to the default Apple/Android mail app. To fix this, the best option is to install the Outlook app and use that instead.
- Install the Outlook e-mail app from the the Google Play Store or the App Store.
- After installation is completed, add their GMU account. Log in through the GMU web portal.
- Go under the Calendars tab in the bottom-right to see their shared calendar and events.
After this, you should be able to tap the icon on the top-left of your screen and see the following menu attached below.
You can add/remove people from the shared calendars with the check boxes. You can also tap any of the cog wheels to edit the color, or add more events/meetings to your calendar. This is categorized by user, so if you add "John Smith" to your calendar, you will see all of "John Smith's" events and meetings.