Cannot open calendar properties

[Puchte]

Hello,

we have Exchange 2016 on prem and Exchange online running in hybrid operation.

Problem: I can't open the calendar properties of a resource mailbox in Outlook. This mailbox is on Exchange Online. My mailbox is on prem. I get the following message: The folder properties cannot be displayed. The folder may have been deleted, or the server on which the folder is stored is unavailable...

I also cannot accept a reservation of the resource.

I have Editor permission and am a Delegate. What can I do?

[#2]

If you have the mailboxes exist in the same org (either both on-prem or both in EXO) this should fix the issue. Lots of things fail to work well when you don't locate the mailboxes in the same org, calendar permissions being one of them.