I have currently facing a problem too much often since I must use "FreeWifi" hotspot. It's hotspot you can use anywhere in France for free id you have login/password.
The thing is that it happens a lot that I cannot connect this network any more without having a DHCP error (see joined screenshot).
It does not come from the AP because when I restart my phone it works again.
My question is, do you know how I can restart N9 WiFi from scratch because it's truelly a pain to restart the phone for this.