Mobile Device Access Rules

1. Check Exchange ActiveSync settings: Open the Exchange Administration Console (EAC).
Navigate to Mobile Devices > Mobile Device Access Rules.
Check that Exchange ActiveSync is enabled. 
2. To configure mobile device access rules: Open the Exchange Administration Console (EAC).
Navigate to Mobile Devices > Mobile Device Access Rules.
Create a new access rule and set the device types, operating systems, etc. to allow or block. 
3. Configure the rule using PowerShell: Open the Exchange Management Shell (EMS).
Run the following command to create a new access rule:
powershell
New-ActiveSyncDeviceAccessRule -QueryString “DeviceModel” -Characteristic “Model” -AccessLevel “Allow”
Run the following command to view the existing rule:
powershell
Get-ActiveSyncDeviceAccessRule
4. To check the device access log: Open the Exchange Administration Console (EAC).
Navigate to Mobile Devices > Mobile Device Access Log.
Check the logs to verify that the device is properly allowed or blocked.
5. Contact Microsoft Support: If none of the above methods work, it is recommended that you contact the Microsoft Support team with detailed error messages and screenshots for further assistance.