April 21, 2020 03:40 PM Addendum
We are pleased to inform you that Microsoft has announced that the problem has been resolved, except for some users.
As of 9:30 on April 21, 2020, it seems that Office 365 connection failures are occurring mainly in Japan.
Problems such as not being able to connect to Outlook have been reported, and we are waiting for recovery by Microsoft.
We will let you know if anything changes, so please wait for a while.