Bought refurbished modem/router combo (SBG10) through Amazon. I worked with Xfinity tech support for a long time, and still not working, even after several power cycles.
All lights light up except the "online" light. Devices can connect, but without internet. Xfinity is unable to remotely detect it.
Simple troubleshooting: yes, it is plugged in. Yes, the coax was in and tightened all the way. Yes, I used the Ethernet port and cable and a computer to do the initial configuration. I have experience setting up modems and routers. I am confident the problem is in the refurbished unit.
I am requesting a replacement of equal value, or greater if unavailable, as soon as I am able to return the unit I have.