We configured Hybrid for this customer and Migrated a small Pilot batch of IT users.
Now in the big orgs we share calendars with the team to keep transparence and block a time for team meeting together so this customer required to share the full details of the calendar.
Instead of searching through Exchange logs I found that you can pin point the exact error message through Microsoft Edge to assist with troubleshooting.
To do so; A common misconception about granting mailbox access rights in Exchange Online is that you can only add access to the individual and not a group.
You may have opened the Exchange Administrator Center (EAC), found the mailbox you wanted and looked at the delegated access tab.
Only to be provided with a list of eligible user identity’s, but none of your on-premises security groups that have been created.
We are in the middle of hybrid coexistence migration from Exchange 2010 on-premise to Office 365.
That means we have ADFS and "Dirsync" (now called Windows Azure AD Sync) running.
If there is no on-premise mailbox when you assign a license, it creates a cloud mailbox.In this article we’re going to create the Hybrid configuration between the on-premises Exchange organization and the Office 365 tenant.The current on-premises environment is running: The Exchange 2016 Mailbox servers are the internet-facing servers for the organization, with a load balancer distributing traffic across them.Moving to Exchange Online has more sophisticated taste that needs to be catered for due to its Evergreen state with all the latest Exchange trends.If you migrate on-premises mailboxes with these slightly incorrect permissions to Exchange Online they will be lost forever.
Globally redundant servers, premier disaster recovery capabilities, and a team of security experts monitoring Exchange Online around the clock safeguard your data.