This white box plugged into an outlet connected to my Xfinity modem via Ethernet cable?
We can't see your pic. Since you are a new poster, it needs to be approved by a Forum Admin. That could take some time. In the interim, you could try hosting it at one of those free third-party pic hosting sites like Imgur or Photobucket and post the link to it here.
It appears to be what the poster @strega7 stated.