Xbox Controller Sync Button

Sync the Controller:
To sync a wireless controller with your Xbox, follow these steps:

Press the Xbox button on the controller to turn it on.
Press and hold the small sync button on the front of the Xbox Series X console (located near the USB port).
While holding the sync button on the console, press and hold the sync button on the controller (located on the top near the Xbox button).
Release both sync buttons when the controller's Xbox button starts flashing. The controller should now be synced with the console.

You have to sync your second controller, via the Xbox One's sync button on the left, and the controller's sync button on the top.

You have to push the sync button on the controller (Next to LB bumper) and the sync button on the front of the Xbox 360 at the same time for the controller to sync properly.

Have you tried syncing that controller to xbox, it is the button right above where you plug your wired controllers into. When you hit the sync button on the console you have to hit the sync button on the controller it is between the right and left bumpers.

On the Xbox 360 right on the left side of the front usb ports is a sync button. On the back of the speed wheel is a small black sync button. Both these buttons must be pressed when the console and controller are on in order to sync the controller to the
console.