ONU Initial Setup at New Address

Hello, I just moved to a new address which has access to xfinity epon 1gig up/1 gig down.

I wanted to self install because the availability for a technician was a week out. So I called and was shipped an XER10, and was told I just needed to follow the instructions in the app to activate.

I attempted and this activation failed several times. After talking to multiple chat agents and calling customer service, I was told it could not activate because my service address was missing an ONU box, and they think the prior tenant might have lost or removed it, so they need to send a technician to install a new one.

However, I was able to locate this onu box in the unit, behind a white panel. The box has all three status lights of PWR, PON, ONLINE as green. I power cycled the box, then attempted to activate the XER10 again but it still failed. 

Is there a way you can help me troubleshoot and get my service working since I found the missing ONU. I don’t mind waiting for a technician but they are over a week out, and I need to work from home.

Any help is greatly appreciated.