We have a Hybrid Exchange environment in-place between Exchange 2013 and Exchange Online.
We have created Mail Contacts on our On-Prem Exchange for users whose mailboxes are in Exchange Online. These contacts have then been added to an On-Prem Distribution List. Whilst they appear in the DL properties, they do not appear when the DL is expanded within Outlook therefore do not receive emails sent to that DL.
I've run:
[PS] C:\Windows\system32>Get-DistributionGroupMember "DL Name" | where {$_.HiddenFromAddressLis
tsEnabled -eq $true}
To ensure no users are marked as Hidden (various online posts point to this being the issue) and also checked the HiddenFromAddressList properties of the DL in question - this is also set to False as expected.
Running the above command with the $false parameter returns 80 address, expanding the list in Outlook returns 66. Some members are themselves lists, does that account for some discrepancy?
I've checked Azure AD Sync and it's working fine.