Mouse not working when in xbox

Check to make sure the cables not lose and then hard rest.

Try performing a hard reset EXACTLY like this. Hold the power button on the console for 8 seconds or until the power shuts down completely.
Unplug the power cord from the back of the console for 5 minutes.
Plug the power cord back in and restart the console.

If that doesn't help. Check the battery in the mouse. Try it on a different device.

You can check the compatibility here:

https://www.windowscentral.com/list-xbox-one-mouse-and-keyboard-games

Hi Joao,

Thanks for reaching out to us here on the Forums!

We understand this can be frustrating since the Mouse is not recognized when playing Fortnite on the Xbox One. This appears to be a rising issue between Microsoft and Epic Games. We are currently gathering data regarding this issue so we can work on a fix/patch.

Does this happen with other games as well? Note: wired USB mice will work only in select games and apps that have enabled mouse navigation. Check your games to see if they offer mouse input. Try to configure your mouse in
Settings > Kinect & devices. There are options for pointer speed and swapping primary and secondary mouse buttons.

You can also visit the Epic Games Forums:
"Xbox One Mouse and Keyboard (Mouse Not Working)" for more information.

I hope this helps. Thank you

In order to keep an equal and fair multiplayer experience, you can only play with controllers on the Xbox One.

Games that work on the PC as well (like for example Gears of War 4) can be played with keyboard and mouse, but you can only play cooperative multiplayer with console owners that have to use controllers, so mouse and keyboard users don't have an advantage.

These XIM4 or Mayflash devices aren't real mouse and keyboard devices. These devices show themselves as a standard controller to the console, and when you move the mouse, the adaptor "guesses" from the speed you move the mouse, how hard it should push a
simulated controller stick in a certain direction.

These adaptors won't give you the same control as the mouse on a real PC.

When you stream the Xbox game screen to your PC, you can also only use a Xbox controller. Mouse and Keyboard won't work as a game input (you can only use the keyboard to enter text when the virtual keyboard is shown).

There are plans to get Keyboard and mouse working, if there ever is a way to stream the PC screen to the Xbox console.

But currently, if you're playing on the Xbox console, it's controller only (even if the controller is "guesstimated" with mouse and keyboard inputs).