Why is my night hawk RAX43 no reading the original cable during set up?

[Rico305]

Trying to set up router through app and once it gets to “cable check” screen, I get an ❌ for cable but cable is original from the box. Cable is fully intact with no visible cuts or openings. I’ve also tried different ethernet cables but to no avail. What can I do?? Thanks!

[plemans]

What is that "cable" connected to? that's kind of the key. 

What modem/gateway is on the end of the cable?