Issues while trying to connect an Arris modem to a Xiaomi AX3000T router

I put my Arris modem in bridge mode, then I connected it to my router (Xiaomi ax3000t). It was supposed to be simple. From the start it did not. Then it gave me these options: I picked DHCP. Then was just others configs and this message says the cable is the problem but I tested the cable and it works just fine, I even bought a new one cat6 just in case, but no the same error:

Question by Laplace'sDemon on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.