Tried everything here without any luck. I was just about to give up when I found a configuration page on my router (Actiontec MI424WR-GEN3I).
- Go to the Broadband Connection (Ethernet/Coax) Properties page.
My Network > Network Connections > Broadband Connection (Ethernet/Coax) > Settings
- Click the buttons for "Release" and "Renew"
- Click "Apply"
- Power cycle the STB (I didn't but you should just to be safe)