We are well aware of a Global issue with missing/invisible text in Outlook on Windows after an overnight update from Microsoft:

https://www.itnews.com.au/news/microsoft-outlook-hit-by-worldwide-email-visibility-issues-564434

We are contacting our customers with Managed Services Agreements to assist with rolling-back the update until Microsoft releases a fix.

As a work around please use webmail (https://outlook.office.com for Microsoft 365 users) or the Outlook app on your phone.

Thanks,

Simon Wong

Director