In the Internet Settings page, protocol should be DHCP, not PPPoE, i.e., no need to enter Xfinity username/password. Please try:
1. On the System Settings page, click “Sync Time with Browser”.
2. On the Internet Settings page, select “DHCP client” for protocol.
2. Wipe out “Override MAC address”. This will restore the MAC address to the default.
3. Click the Save button at the bottom of the Internet Settings page.
Wait for 5 minutes and check the Status page again.
If the Internet status is still down and you want to try overriding the MAC address, take the MAC address of the computer you connected to the modem previously and put it in the “Override MAC address” box.