An error occurred while saving the commentBob Klinger commented
Currently if your are a GCC Customer your Outlook Mobile App is restricted to one mailbox account per device. Once you add your GCC Enabled account to Outlook App you cannot add any additional email accounts. There currently is no documentation on how to disable or make an exception for a Global Administrator to opt out of these GCC restrictions limiting 1 account to Mobile devices using the Outlook Android/iOS app.
The Outlook for iOS and Android architecture is FedRAMP compliant for US Office 365 GCC customers
Q: Will Office 365 GCC customers be able to add an account to Outlook for iOS and Android in non-GCC mode?
A: No. GCC users will continue to be blocked from adding accounts with Outlook for iOS and Android as that process routes data via the public Azure cloud instance. Controls are in place to ensure all GCC mobile users use the “GCC Mode” to connect Outlook with their Office 365 account.
Q: Once a user enables “GCC Mode” can they add an additional Office 365 account?
A: No, Office 365 Government Community Cloud customers may only have one account connected to Outlook for iOS and Android from a single Office 365 instance. This means that these customers cannot have a mailbox that is located on a different Office 365 tenant, from either the public Office 365 instance or the Office 365 Government Community Cloud tenant within the same Outlook for iOS and Android app on the same device.
Using Outlook for iOS and Android in the Government Community Cloud
Office 365 Roadmap - Outlook for iOS and Android in GCC
Outlook for iOS/Android App Availability for Government