Microsoft has restored the ability for Safari Users to log into the Office 365 email service.

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Previous Description (December 6, 2019 13:09):

The Safari web browser on MacOS Mojave is currently failing to allow users to log into their Office 365 email. Microsoft is aware of the problem and have provided the following work arounds.
- use another web browser
- use the Outlook desktop application
- upgrade your MacOS to Catalina

This notification will be updated when the problem is resolved or if the problem changes.