Keeps turning off!

Unexpected shutdowns usually point to either the console overheating, or a power supply issue.

This support article should help point you in the right direction: https://support.xbox.com/en-US/xbox-one/console/console-turns-off-unexpectedly

Been sent that link and dosent take me anywhere and it dosent let me press the link you've written. My xbox one x can happily play games all day as soon as it comes to matchmaking a game on the new cod it's overheats or overheats whilst I'm in the game
I can play the career mode on cod no problems soon as it comes to online it turns into the worst console I've ever owned (coming from a xbox person aswel).

Can you provide some more information, so we can assist you better with this problem?

Do you have an original Xbox One or a One S / One X?

In the meantime, here is the support page for power issues:

https://beta.support.xbox.com/help/hardware-network/console/console-wont-power-on

Hello, try following the steps from the following support page:

https://beta.support.xbox.com/help/xbox-360/console/console-turns-off-unexpectedly

https://beta.support.xbox.com/help/hardware-network/console/console-turns-off-unexpectedly

Hope this helps