Shared calendar in Outlook - "Folder not available"

[MrBig]

I'm trying to set up a shared calendar in outlook 2016 between me and 4 of my colleagues. 2 of them have been able to access it no problem and the other 2 are getting the message "The folder you selected is not available".

I have checked all the permissions are correct, and tried it repeatedly, even with someone else setting up the calendar but then I get the same error message. We have an external IT contractor but hes seemingly unable to fix it too. Any ideas please? I'm not even sure what folder it is referring to? The folder on my PC where the ics file is stored? Does this folder need to be in a location where all my colleagues can access it? If so, can it be on dropbox?

Apologies for many questions and much incompetence!

[sparkyhx]

i know our it were having problems with domains, in that different email accounts wer on different servers and it was a cross domain issue.

dont know the technical detail or the solution, but it might be an area to check.

[sc0tt]

Try setting the permissions in powershell on the exchange server. I usually find more successful than using the GUI.

https://docs.microsoft.com/en-us/powershell/module...

Let me know how you get on.

[CharlieCrocodile]

Where is the shared mailbox? Is it an Exchange mailbox or something else. You mention Outlook, but that's just the mail client, not the mail server.