Have you tried simply unpluging the power from the box for a minute or so?
If not, try that
If that doesn't cut it, unplug the power to the box, unscrew the COAX from the box to the wall, and check the pin in the middle to make sure it is not bent or broken... Do the same at the wall jack, if applicable... If all is well, plug it all back up, turn it on, and test it out....
If still not resolved, reset the router with a paperclip or pen in the reset hole on the back of the router for 15 seconds (yes the router.. the rotuer for the internet), reboot the STB and try again.
If that still doesnt work... Call 1 888 553 1555 for Technical Support