Not recognized by modem

I had my airport extreme downstairs connected to my mode, I woke up today and had no internet, I went down and the airport looked fine, the light was green.

The modem however was not blinking where it should be so I thought it was the modem but the modem worked with Ethernet.

So I took it upstairs where we have a diffrent modem and the same thing, it does not see the airport extreme but it recognizes other routers.

Any idea why and what I can do?

Thank you