Exchange Office 365 - Delegate Calendar Issues

[adamms1]

Hello,

We run Office 365 and only have the exchange service, so MS manages our emails.

We all run Macs and use iCal for our calendars and Mac Mail for email.

This configuration has been running for 3 years with no trouble.

This week I have been getting error messages on my calendar, nothing clear on why this was happening I checked through all settings and noticed all the calendars I have access to now show 'No Access' under the Calendars column. Once I removed all the calendars the error went. 

I then tried re-adding the calendars, no luck.

Nothing has changed, all 5 users who share their calendars with me went off on the same day. I've checked and we all have primary calendars no secondary.

I've checked all our accounts using webmail and we all have access to each shared calendar.

So the issue is specifically to do with iCal. 

Has anyone seen this issue? Or know of a fix?

Any help would be appreciated.

[#2]

The good news is you have already done enough work to isolate down the problem to your mail client, and you have a date it started.

The bad news is there is likely not much help people are going to be able to provide you here on the Microsoft forums. Because you know when the problem started and that it is isolated to your iCal's I would try either the apple forums, or even opening up a support case with apple directly.

Having worked in IT support around email though, I can tell you that you have done 90% of the work with your testing, you just need to find vendor specific help now with Apple.

Here is the iCal support section directly for you - https://www.apple.com/support/ical/index.html

Goodluck!

Adam

[#3]

Thank you so much for coming back to me.

I've gone down the Apple route and i've been told that nothing has changed with iCal or OSX to cause this.

I then tested my MacBook, and a secondary iMac and they are the same.

Everything is pointing to a permission change in Exchange that is revoking these third party requests. 

So we have 3 iMacs, 4 Mac Minis & 3 Macbooks that no longer Sync. All on different OSX versions.

[#4]

Update to this.

Everything is back up and working.

I CHANGED NOTHING.

Looks to have been an issue with MS and Exchange. 

Nothing noted on the admin panel of Exchange, so unsure what they broke and then fixed.