Occasionly my N9 stops communicating with my WiFi even though it is still showing that it is still connected, solution is to reboot the phone.

In the past my N96 failed to connect to my WiFi while everything else would, I rebooted the phone, took the battery out and eventualy took it to get repaired where it connected happily to the repair shop's WiFi, solution was to reboot my router, I felt a little stupid for not thinking about that. Routers can fallout with a device for no reason, reboot your router and see if that helps.