"The Group Policy is automatically updated (refreshed) in the background every 90 minutes, with a random offset of 0 to 30 minutes. You need to wait for 120 minutes to check if the GPP you customized work normally or not.
If you would like to modify the refresh interval and the offset interval for users, please modify and apply the group policy: User Configuration\Administrative Templates\System\Group Policy."
For more information, please refer to the following links: