Hello Herry-8182,
Thank you for posting in our Q&A forum.
What error message did you receive when you add Windows Control Panel> Internet Options > Security Tab > Trusted Site > Then add the Site in Trusted?
If there is no any error message, please check if any group policy setting on DC blocked it.
1.Logon one of the domain systems using domain Administrator.
2.Open CMD ( run as Administrator).
3.Type gpresult /h C:\gpo.html and click Enter.
4.Open gpo.html and check whether there is gpo setting about Computer Configuration > Administrative Templates > Windows Components > Internet Explorer > Internet Control Panel > Security page > Site to Zone Assignment List under "Computer Details".
5.If there is such gpo setting, then you can Add Website in Trusted Site via domain gpo.
For more information, please refer to link below.
https://www.isunshare.com/windows-10/add-trusted-site-to-group-policy-in-windows-10.html#:~:text=How%20to%20Add%20Trusted%20Site%20to%20Group%20Policy,tap%20on%20Show%20button%20under%20Options.%20See%20More.
Hope the information above is helpful.
Best Regards,
Daisy Zhou
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