As of 3:51 all users are confirmed as failed over and operations are back to normal. We will continue to work with Microsoft to ensure this bug / issue is properly diagnosed and leads to a more permanent solution.
Update 02/25/2020 20:38 PM 26 days
Service restart has forced the mailbox instances to start failing over. We should have services fully recovered for all users shortly.
Update 02/25/2020 20:24 PM 26 days
We are experiencing a minor outage affecting 84 mailboxes on our Exchange 2016 platform. Our teams are trying to determine why the failover did not occur correctly, and out of abundance of caution, we aren't terminating the system call.
In the meantime, all 84 users affected by this Exchange database outage can still send and receive email at https://livearchive.exchangedefender.com while the maintenance is underway.