I think it’s 26.2 that finally did it, but I pulled my hair out for a while, but finally got it working. Here is the magic command. WTF Apple?
Make sure to replace “your.server.com” with the actual name of your server. Might be Bonjour like yourserver.local. Also, make sure it is lowercase.
sudo /usr/libexec/PlistBuddy -c 'Add :your.server.com bool true' '/private/var/root/Library/Group Containers/group.com.apple.NetworkAuthorization.ServerMarkers/serverMarkers.plist'