Share Point Online is also involved as it provides a shared document library, which includes a shared One Note notebook.
To save resources, the shared document library is not provisioned until the first time that a member attempts to use the “Files” functionality for the group.
If you can see the appointments in your shared calendars online then the issue is more than likely due to the cache on your Outlook needing refreshing, here are the steps to fix the problem: Please note.
If you are not sure that you are using hosted exchange please do not follow these steps as incorrectly deleting the Outlook data file may delete your Outlook email permanently.
However the second mailbox shows only the folder with no mail, until I click Send / Receive - Update Folders, then it downloads fine and I can read the mail.
If you are making use of shared calendars in Outlook 2016 you may find that not all appointments are showing in the calendar or are disappearing.
Typically this happens when running Outlook 2016 in cached mode with exchange or Office 365.
The easiest way to verify this is the problem is to log in to your Outlook Web Mail, if you are using Office 365 you can log in at https://portal.using your username and password.
If they want, users can subscribe to a group and interact with the group completely via email.
The shared document library functions in the same way as any other Share Point document library. Instead of access being granted to the library as users join a group, membership is resolved whenever a user attempts to access a library. Microsoft would like Office 365 Groups to become a user-driven method for collaboration, so the default is to allow anyone to create a new group.