What does it mean "3 Devices Not Connected." Do I need to fix this?

We have an Xfinity cable modem provided by Xfinity. When I go online and check my Xfinity internet security (https://internet.xfinity.com/connect) under my account it says, 3 Devices Not Connected. What does that mean? Is that a problem? I see two of our Windows 10 PCs and our Netgear router on the list, all working fine.

The page also says the last time all three of these devices were connected was November 30. Why did they become unconnected?

There is no option on the Xfinity web page for "connecting" these devices, and nothing indicating whether this is an issue or not. Is this something I need to attend to?

Thanks.