|Your internet connection has little to do with your issue.|
I take it you are trying to use your mobile internet connection for the xbox?
To do so you need the following;
a wired network connection in the laptop in addition to the mobile connection
you would need to engage bridging or ICS between the interfaces
if using bridging you would need to assign a static ip to the xbox
if using ICS it will get a dhcp ip from the laptop [you have to set the xbox to obtain ip automatically]
You would need to open/forward the xbox ports in the laptops windows firewall. You can get those ports from portforward.com
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