Outlook (Classic) can't open after one of the Exchange 2019 server died.

Question

We have 3 Exchange mailbox servers, two 2019 and one 2016. One of the 2019 server died and some of the user's outlook won't open and receive the following message.

Cannot start Microsoft Outlook. The set of folders cannot be opened. The information store could not be opened.

Seems like the Outlook connection is stuck on the Exchange server that is offline. I was able to resolve the issue by removing the old outlook profile in Mail and re-create it. Why didn't the outlook use other Exchange servers that are online when the existing connection died? Is there some cache in outlook I can clear or my autodiscover is having issue?

All my autodiscover internal URL is https://mail.mydomain.com/Autodiscover/Autodiscover.xml and we are not do DAG or any clustering on our Exchange enviornment.

Answer 1

Are you using a load balancer for the client connections? If not, then Outlook can get stuck on the DNS entry to the dead server if its not pointing to a load balanced pool.

Answer 2

Hi @Wang Lee,

Thank you for raising question to Microsoft Q&A.

According to this issue, may I know if during the time that one of the 2019 server died - did you check on OWA? Did it still provide the connection and the database with problematic mailboxes still be mounted?

If the database does not mount and work normally then the mailboxes cannot be connected.

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Answer 3

The server that died doesn't have any active mailbox in it. All the users mailbox is on the database that is online.

And the users that has issue were able to use OWA to access their mailbox.