I have the same problem.
I try to connect from other network and i can't do it, The password are ok, but when I click ok, the browser show the login form again.
If I put a bad password, the browser shows Wrong passwrod, but if i put the correct password, the form is reloaded.
If I connect the computer to the same network, connected directly to the switch, all works fine.
Any idea ?
Thx.
Armando