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DeadAuroraUz's avatar
DeadAuroraUz
Copper Contributor
Jul 16, 2026

Exchange 2019 + ADFS is it possible to configure ModernAuth for third-party Android mail clients?

Hello, Our organization operates under Uzbekistan's data localization and banking secrecy regulations, which require customer and corporate data — including email — to remain on infrastructure p...
2019
Exchange Server
oauth2
On prem exchange EWS
Jamony's avatar
Jamony
MCT
Jul 19, 2026

Your configuration is working; the client support boundary is the blocker. Microsoft’s current guidance lists EAS as capable of ADFS Modern Auth, but supported-client behavior is specific: Apple Mail on iOS 17.6.1 or later uses it, while Outlook for iOS/Android and Gmail fall back to Basic in a pure on-premises deployment. Arbitrary third-party EAS clients are not documented.

 

Do not use New-FlightOverride to bypass OAuthNotAvailable. Flight settings are not a supported client-enablement method and may change with updates. Nine must implement the ADFS OAuth authorization flow, provide a registered client ID and redirect URI, and use the advertised authorization endpoint. Confirm those capabilities with NitroDesk; Exchange cannot force a Basic-only client into OAuth.

 

Apple Mail works because Microsoft’s setup registers Apple’s native-client identifier and redirect URIs in AD FS. That client-specific registration explains the redirect; it is not a generic EAS challenge every client automatically follows.