Forum Discussion
Issue with security defaults - activesync clients get quarantined
We are seeing issues after enabling Security Defaults where activesync clients get quarantined in Exchange Online and cannot be approved. O365 Support have been unable to tell us why or fix it. ...
Security defaults block legacy auth, which is the most likely reason here.
Many iOS mail app clients work fine with Security defaults enabled. iOS mail supports modern auth, and I don’t think activesync is a legacy protocol?