I wish I could find a screenshot of this but what happens is: You want to modify a GPO that is pushing firewall rules and you go to change them and you get a red box saying something about ‘cannot connect to the domain’ only in that section of the GPO, other settings work fine.
1a. The fix is to find your PDC Emulator
Get-ADDomain | Select PDCEmulator
- RDP to that DC and then try editing the rules, it will then work!