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Luke_IT's avatar
Luke_IT
Copper Contributor
Apr 18, 2023

Exchange Hybrid: Shared Calendar issues with Outlook

Since approx 48hrs ago we noticed Outlook not receiving new calendar updates / meetings from on-prem Teams rooms calendar mbox in a hybrid scenario. The Teams room calendar itself receives the invitations and meeting schedules as normal but the people who created the event and invited the room do not see it in the Teams Room calendar they have added in their Outlook (though they receive the meeting invite on their email and personal calendar) whether they have ownership permissions or not. This has always worked fine until now. The only way I found to workaround this issue is to *disable cache mode* in Outlook. I tried removing the calendar and re-adding it to no avail. Removing the cached mode, deleting the cache files and re-enabling the cached mode will not resolve ths problem and the Teams Room calendar will remain all BLANK and not update: I verified the correct connection to the on prem endpoint and it is correct and no errors are reported (same connection with cache disabled of course). This points to an Outlook 365 operational issue or bug and not Exchange itself in general so I don't know if this is the correct group to point this out but it does involve Exchange Hybrid mode.

Steps to reproduce the issue:

Enable cached mode in Outlook 365 in a Classic Hybrid mode scenario. Add a shared (Teams Room in my case) ON PREM calendar. to your mbox in Outlook (you can additionally set ownership permission on the shared calendar but it doesn't change the result). Verify the absence of displayed events. Disable cache mode and restart Outlook, the events will appear.

 

    • Luke_IT's avatar
      Luke_IT
      Copper Contributor
      I have not tried to revert back to cached mode on those machines with O365 (the ones with 2016 and 2019 work fine). At the moment they are working fine with online mode and I will leave them like that for the time being until I manage to have a maintenance window and try cached mode again if I see the Outlook 365 version has been updated.
  • Simo_baz's avatar
    Simo_baz
    Brass Contributor
    Teams rooms in onpremise exchange is not really supported as far as i am aware, to support full functionality you should use exchange online mailboxes.

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