You may have noticed that some of your users cannot access email after they have an iOS compliance policy assigned to them. One of the reasons could be because they may have deferred setting a PIN or a passcode after an iOS passcode policy is applied.
When users on an iOS device are targeted with a passcode compliance policy, they will be considered ‘not compliant’ until they set a PIN. Any company resources protected by Conditional Access policies requiring a compliant device will be blocked until the user makes their device compliant for the assigned policies. If they choose to defer setting a PIN, they will be prompted every 15 minutes to set it, until a PIN is set.
Note that devices that are locked after being marked not compliant will lose email access until they are unlocked and a PIN is entered. End users on these devices may experience a delay of a few minutes until their email is updated again.
We hope this helps! Let us know if you have any questions or feedback.