Windows changes its behavior if the network is public or private. When first connected to the network (its idea of a given network is “this router MAC address”) it asks to the user if this is a private or public one.
If the user says “public”, it gets heavily firewalled, and a buch of services are disabled on the network.
So, I’m just wondering if it changes the browser’s settings too. Maybe it is blocking your pop up, javascript or whatever. Have you checked this?