When trusted sites are managed by GPO we can’t even view what servers are trusted using IE menu Tools > Internet Options > Security > Servers because the UI is disabled and won’t let you scroll down:

To solve this problem, from a command line in admin mode:

$(get-item “HKLM:\SOFTWARE\Policies\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMapKey”).property

$(get-item “HKCU:\SOFTWARE\Policies\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMapKey”).property