Ineligibly Modem for My WiFi

Let's try this again. My modem is the Arris DG2460 (Dual Band WiFi). I am currently renting it from Cox.

I can not use the My WiFi service at the Cox website. When I do, I'm redirected to a web page that says I have an ineligible modem. I click on the button that says "Learn More," so I click it. 

What I learn, is my modem is eligible for using My WiFi according to the list provided. Here's a link to the COX web page that says so. http://www.cox.com/residential/support/internet/article.cox?articleId=fd8e4d10-46e7-11e6-d0df-000000000000.

So please help me understand why my modem is ineligible.

Thank you.