We test the logon system before putting out an update of course. Is it possible some other change was on the PC? Is GlassWire blocking itself? If you leave your password blank temporarily does it work?
A firewall issue. Somehow the server ended classified as Private network with no remote access (noticed no RDP, no SMB too).
After disabling and reenabling rdp and sharing also Glasswire remote monitoring worked.
Very weird as I checked the firewall rules and there already was a rule allowing glasswire was in place and active before doing this, and the reinstalling of glasswire should have done the trick.
Anyway now it works.