We've set conditional access policies to control MFA to specific apps and resources. In 2 of those CA policies I configured a different sign-in frequency. One for external virtual desktop access (like 24 hours) and one for mobile Outlook App access (like 7 days).
By excluding Office365 Exchange Online in one CA policy and including it in the other this works fine for the Outlook app on iOS. You see it is accessing the resource named 'Office365 Exchange Online' in the sign-in logs and activating the 7 days sign-in frequency.
Android users however are complaining they get the 24 hours sign-in frequency. I've noticed a different resource named 'Office365 Exchange Microservices'. This is not a cloud app you can select in the pull down menu to exclude or include.
How can I mark or filter this resource in our CA policies?