In case you don’t subscribe to the Microsoft Online Service Notifications, the below link describes a planned maintenance outage on June 19th to the Microsoft Online Customer Portal (MOCP).
All other services and functions will continue to work normally.
https://rss.apac.microsoftonline.com/additionalinfo.aspx?fid=fae1198e-dbea-4dd0-8d3f-c2bec90241dc