Why, after factory reset, I can't pair my controllers?

My Quest 2 fell off. However, I could continue playing with no issue. After I exited the game I was playing (10 or 15 minutes after), it started giving me the "tracking error".

Being unable to fix it, I factory reset the headset. Now, when I try to do the initial setup, I can get the controllers to pair with the headset, and they keep buzzing every 10 or 15 seconds.

Could this be a headset problem, a controller problem, both? How can I fix it?