Mac Users Trying to Delegate User Access | Fails on Mac and Outlook on the Web

Occasional Contributor

We have several Mac users who were able to delegate user access to Calendars at one time, and now are not able to.  They are also unable to delegate access via Outlook on the Web.  PowerShell works for an Admin, and the users can "Share" their calendars, just not "Delegate" access to it.  When they do - they receive these errors, in their respective clients and online:


Office for Mac Client: "Outlook cannot delegate one or more items | An Error Occurred while contacting the exchange server"


Outlook on the Web: "The Sharing invitation couldn't be updated"


Both users have Macbook Pro's running Mac OS High Sierra version 10.13.6

Outlook for Mac is version 16.20 (181208).


We have tried already: 
Pushing all updates to both OSX and Office.  (Failed to Fix)

Forcing the delegation in PowerShell (Works).

Validated owner permissions for both user's Calendars.

Validated correct Calendar trying to be delegated.

Can see other previous users that were delegated by the users.

Cannot edit existing users or add new ones for delegation rights.

Forcing Owner rights on the user's calendars and removing it.(Failed to Fix)

Forcing Owner rights to another user and then back to the original owner. (Failed to Fix)



2 Replies

You might wanna open a case with O365 support here. If you did please PM me the case nr so I can have a look into it :) 

All the best


@Justin Cohen - Did you found any solution for the mac user to add delegate access? we are having same issue . share the solution if you found any