I’m trying to connect my Xbox series S to my brothers Xbox series X.

Hello Minh Nguyen2,

I got an update from our internal team, if the final troubleshooting steps provided and if SwordofWhedon
advised did not work out. it is advised that it would be best if you reached out to the Internet service provider for this issue.

Hay carTzy

It’s unmanaged, is there anything I could do from here?

You sure it’s a crossover cable? That should just work.

Your next step would be to get a switch.

Hello Minh Nguyen2,

If it's unmanaged, then typically each device should be able to communicate with each other.

Try assigning static IP on your console and see if this works

Home Menu, select Settings.
Select Network > Advanced settings > IP settings > Manual.
Choose the IP address then select Enter. (example 192.168.110)
Subnet mask. Select Enter. ((example 255.255.255.255)
Gateway. Select Enter. ((example 192.168.1.1)
Advanced settings then select Save.
After saving the changes, go back to Network settings then select Test network connection. Wait until the test finishes checking your network connection status. An “It’s all good” message will appear when it’s finished.

You may also want to try the method below to connect consoles together.

How to use system link to connect multiple Xbox 360 consoles | Xbox Support

Hello Minh Nguyen2,

Are you using a switch? - Yes

With regards on the switch that you are using, Is this a managed or unmanaged switch?

If this is managed switch, try to check if both devices are connected on the same VLAN, make sure that both ports are on the same VLAN.