There is a current issue when some players get an error message about their controller. You get this message if you are using a controller bought from a 3rd party website. This isn’t official but with these error messages, it will be obvious that they intend to ban all 3rd party accessories/ controllers

When you connect these unauthorized controllers, you will receive the error code 0x82d60002. You will have a 2-week grace period with these controllers/ accessories then the error message will pop up. There has not been a public announcement from Microsoft so it has not been confirmed but it seems like the error message can confirm this.

The only accessories and controllers allowed through the Microsoft hardware partnership program. These accessories and controllers will be considered authorized and will be able to roam freely throughout the Xbox world. 

It is not clear why they would do this at all but for the money. The possible reason behind this is to cut down the cheating population and make a safe, hacker-free environment. Another possibility is that it is for the money and they want to sell more controllers.