Message number: 201910231530
Period: from Oct 22nd, 2019
Affected: Exchange users
Impact: sporadic and temporary logon and access issuesSince October 22nd, 2019, Exchange users are affected by increasing
sporadic and temporary login or access issues. These issues are
observed in the context of ongoing work to optimize the Exchange
environment. An immediate cause is not obvious, but Microsoft is
involved in solving the problem.