Adding Calendars

Question

Exchange 2016 Hybrid mode, we upgrade clients from Office 2016 to Office 365 when they have been moved to Exchange Online

We have a strange issue where users that have been migrated to Exchange Online are unable to open a calendar of a colleague, who has also been moved to Exchange Online, using the "Add Calendar" button in Outlook 365 application. When they click on the add calendar button they get the message "We can't add the calendar of persons_name now. Please try again later."

We found a workaround to this issue by getting the affected users to connect to www.office.com and then adding a calendar in there. When they return to the Outlook 365 application the calendar they added within office.com/OWA is now available and strangely they can now add any other calendar using the application.

Has anyone else had a similar issue?

It seems to me that something is being blocked at the application level but is fine when using a browser, however, once you have added using the browser you are then able to add further calendars using the Outlook application.

Answer 1

@Hiorns, Neil

Glad to see you have found a workaround for this issue.

Based on your description, the Calendar could be shared from OWA, I think there doesn't exist issue with the mailbox.

This issue may be caused by cache on Outlook, I would suggest you try to recreate Outlook profile for this mailbox again, or try to run Outlook in Online Mode, check whether could share Calendar for them now.

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Answer 2

Chiming in on this, as I've also seen this error message and it seems to be a rare thing. I've used the "recreate Outlook profile" suggestion given by KyleXu-MSFT and it worked! User finds that all calendars open as expected.

Answer 3

I had the problem with two pilot users whose mailboxes I had migrated to EXO (365) in a Exchange Hybrid environment (actually they got a new Mailbox and the data was transferred from a foreign forest). They experienced the problem with delegate access to room mailboxes which were still located on the Exchange Server On Premise. After turning off calendar improvements following the following community threads, adding room mailboxes calendars to the calendar view within Outlook 365 under Windows worked perfectly fine immediately.
https://techcommunity.microsoft.com/t5/microsoft-365/can-t-add-calendar/m-p/3259325

https://answers.microsoft.com/en-us/outlook_com/forum/all/we-cant-add-the-calendar-for-right-now-please-try/32ec2cb5-57ec-466e-8613-dc8e2744b660

I don't really like that, but for the migration scenario expected to end October 2025 I think I'm going to enforce the disablement of calendar improvements by policy.