Outlook disconnected when Exchange in Maintenance Mode

Gavin Ross 231 Reputation points

Having some strange issues when we put our Exchange Servers in maintenance mode when doing a CU update. We have 4 Servers and 2 DAGS, when we put the primary server into maintenance mode, we get disconnected in Outlook. Everything else works fine, Webmail, E-Mail to phone, just not Outlook. Does anyone have any suggestions on what might be causing this? When I do a test in Outlook, it is pointing to the correct Internal/External URLS and the test comes back fine. It just will not connect to the Database on the failover server?

Exchange 2016
4 Servers
Kemp Load Balancer


Exchange Server Management
Exchange Server Management
Exchange Server: A family of Microsoft client/server messaging and collaboration software.Management: The act or process of organizing, handling, directing or controlling something.
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  1. Andy David - MVP 145.1K Reputation points MVP

    When you set to maint mode, do you also reboot the server after that to clear any connections?