Hey @abc575183221,
What you're describing sounds like it could be an IP address conflict between the two Xbox consoles on your network.
When you have the chance can you try setting a static IP address for both consoles to see if that helps? The Port Forward website has some instructions on how you can set a static IP address if you need more info.
Please let me know how that goes once you've had the chance to give it a shot. Thanks!