If you have tried restarting the device then a hard restart may help. This can be done by holding down the power button for a total of 40 seconds. You will note that the screen will go dark at 7 to 8 seconds but keep the power button held down until you reach at least 40 seconds. Once done, release and try to power on. If you still have troubles with the connection than I recommend trying to connect to the specific WiFi network with a different device. If neither of these work, please add a message so I can help some more. Hope this works!