Forum Discussion
Configuring Delegate access via PowerShell.
It will be doable via PowerShell in few days, I cannot share more until the official documentation is posted. Until then, you can use EWS to manage them, there's a good module here: http://www.flobee.net/powershell-module-for-managing-exchange-2010-mailbox-delegates/
If using EWS seems to complicated, just wait a bit :)
Did you find a solution? I get the same error when using the command -SharingPermissionsFlags Delegate.
Yes, it was an odd fix but Microsoft had me clear the user's local free/busy time using MFCmapi and that resolved the issue. It did take a while to replicate so after you remove the free/busy info, wait a day then try again.
https://support.microsoft.com/en-us/help/958443/you-experience-issues-in-outlook-when-you-try-to-configure-free-busy-I