First thing, if you haven't done it, is to power cycle / reboot the router. Second, make sure you are connecting to your router, not a neighbor's. lastly, forget all connections on the N7 and start over. Hope you get it working.
I did the OTA update to 4.2 on my N7. Now I can't download anything from the Play store. If I try to purchase or update I get the message: "xxx could not be downloaded due to an error. (Error receiving information from server. RPC:S-5:AEC-0)". Any ideas?