Problem
You want to be able to read, respond, and organize emails in your USJ email account from your iPhone.
Environment
All iPhones
Resolution
- Microsoft Office 365 no longer supports the Apple Mail App on iPhones.
- USJ and Microsoft suggest to use the Outlook App found on the App Store.

Link: https://discussions.apple.com/thread/254266149
Cause
This procedure will give you access to your USJ email account to your iPhone.