Exchange 2019 : Internal User shared calendar not syncing

Question

Recently we updated the SSL cert for an Exchange 2019 server, this broke Autodiscover and we had to reset some virtual directories and add SAM's to SSL to get working. Long story short, external autodiscover is working and passes the Exchange AutoDiscover MS checker tool. However there are some weird left-over bugs.

All internal users now have a certificate pop-up that has the internal server name instead of the name on the certificate. Running

Get-ClientAccessServer -Identity (Server) | fl   

shows that -AutoDiscoverServiceInternalUri is set to the correct https://mail.externalserver.com/AutoDiscover/AutoDiscover.xml so I'm not sure where the internal network user is getting the internal address or cert after resetting the profile. This may be a separate issue, and aside from the pop-up may not be causing issues.

The other issue is that even though mail flow is working fine desktop/mobile both internally and externally, the internal user who we reset the profile now is not syncing on shared calendars. Strangely enough, OWA works (accessing OWA from internal) and she can access and update events and they show for all other users of that shared calendar. But even though she has access to the shared calendar via Outlook on her desktop, no changes/updates/new events she adds sync to any other user.

Verified permissions to the calendar correct by adding same permissions to another user that accesses shared calendar externally and they can change/update/add events just fine and they propagate for all users of that shared calendar.

Any thoughts or pointers would be much appreciated, thanks!

Answer 1

Hi @pwbguy ,

Thanks for your reply and sharing.

Great to know that you've already thought of solution and really appreciate it for your sharing!
By the way, since the Microsoft Q&A community has a policy that "The question author cannot accept their own answer. They can only accept answers by others." and according to the scenario introduced here: Answering your own questions on Microsoft Q&A, I would make a brief summary of this thread:

[Exchange 2019 : Internal User shared calendar not syncing]

Issue Symptom:

1. This certificate pops up on all internal LAN outlook clients every time they open since the internal .local name of the exchange server is not on the SSL cert.
2. Even though mail flow is working fine desktop/mobile both internally and externally, the internal user who we reset the profile now is not syncing on shared calendars. But OWA works
   Verified permissions to the calendar correct by adding same permissions to another user that accesses shared calendar externally and they can sync well.

The Solution:

1. The final fix for the certificate popup was ensuring all VirtualDirectory internal URL/Uri's pointed to the same external, as well as setting the external site record for DNS to the internal server (not internal to external as might be assumed)
2. The issue where internal users can access shared calendars, but no changes/update reservations is resolved with the following steps
   • Reinstalling Outlook (and/or resetting profiles)
   • Removing all Outlook AppData (both Roaming and Local)
   • Removing Autodiscover Registry entries
   • Removing all .xml autodiscover files from User Outlook folder (where .pst/.ost files live)

You could click the "Accept Answer" button for this summary to close this thread, and this can make it easier for other community member's to see the useful information when reading this thread. Thanks!

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Answer 2

If you want to let multiple users in your organization use the same calendar, try the shared calendar included in the Shared Mailbox. The shared calendar is made for multiple users using the same calendar. Any member of the shared mailbox can create, view, and manage appointments on the calendar, just like they would their personal appointments. Everyone who is a member of shared mailbox can see their changes to the shared calendar. To learn more about Shared mailbox in Office 365, here for your reference:
Create a shared mailbox
Open and use a shared mailbox in Outlook
Otherwise, if you still want to use the same Exchange account for multiple users, I suggest you try to use Outlook Web App (OWA) that connects directly to the Exchange server to see how it goes.

Answer 3

For future reference: the final fix for the certificate popup was ensuring all VirtualDirectory internal URL/Uri's pointed to the same external, as well as setting the external site record for DNS to the internal server (not internal to external as might be assumed), seems counter-intuitive but it worked and we now no longer get the internal certificate pop-ups.