Block e-mail configuration on IOS

Hi Paulo

Edit: As I was typing this I've just tested this on my device and it seems that Gmail app on iOS does indeed allow users to set up their Office 365 mail, even if Conditional access requires the use of an approved app AND blocks ActiveSync connections. I'm going to raise this with Premier Support to investigate.

You want to take a look here and make sure your conditional access policies are set up correctly: https://docs.microsoft.com/en-us/intune/exchange-online-protect

Essentially, you need to set up one Conditional Access policy that forced iOS and Android users to use approved apps only (i.e. Outlook).

Then set up a second Conditional Access policy that blocks the use of Activesync on iOS and Android for accessing Exchange Online.

So long as you ensure that ActiveSync connections are blocked, then it should prevent the Gmail app on iOS devices from being used.