@Handian Sudianto, Thanks for posting in Q&A. In Intune portal, to check the policies applied to one user, we can go to Troubleshooting + support > Troubleshoot., enter the user name, it will list the policies applied to this user.
To check policies applied to one device, we can find the information under device-> device configuration:
On device side, we can check the Advanced diagnostic Report to check the policies applied. Meanwhile, we can collect DeviceManagement-Enterprise-Diagnostic-Provider event log when there's error to deploy any device configuration policy.
Hope the above information can help.
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