I am assuming that your other devices / computers connecting to the wifi are working, and that the DHCP is on the router which is letting you get an IP address.
Check the network settings on the tablet and see what IP address your router is getting, even though it cant connect you might be getting the std self assigned IP 165........
Option 1 -> Check the IP addresses of other machines or devices on the network and input similar details to the tablet and see if you able to connect
Option 2 -> I had an odd issue like that once where some of my devices would not connect, I simply changed the channel number of the WIFI router and it was able to connect.