Tablo supports WPA and WPA2 authentication for Wi-Fi. If your router is using an older, less secure authentication method for security (such as WEP), you will need to switch to WPA/WPA2.
Make sure no cable is attached to the Tablo’s Ethernet port. If Ethernet is available, the Tablo will not enable Wi-Fi.
If you want switch from Ethernet to Wi-Fi, first remove the Ethernet cable from the Tablo, and then reboot the Tablo. To reboot your Tablo, press and quickly release the blue reset button on the back right of the box.
The Tablo will then boot into Wi-Fi setup mode. Instructions for this process can be found here.