Problem with setting online mailboxes


I have a problem with setting online mailboxes. They work only with other online mailboxes but not with those that are on-premise. As an example, I set up a meeting with 3 people outside of my firm and one of my colleagues, sitting next to me. They all see it but room does not see that one person next to me. Can someone give pointers on how to fix this?

Hi @Walter,

I assume its a hybrid environment. You need to add on-premises mailboxes to an on-premises room list. To do this, open the Exchange Management Shell on the on-premises Exchange server, and then run the following cmdlets:
New-DistributionGroup –Name <NameOfRoomList> –roomlist
Add-DistributionGroupMember <NameOfRoomList> –member <OnPremisesRoomMailbox>

Note A room list has a limit of 100 room mailboxes per room.

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