Hello
you need to edit recalbox.conf and active xboxdrv driver.
https://github.com/recalbox/recalbox-os/wiki/recalbox.conf-(EN)
it must resolved the problem

------------ D2 - XBOX Controllers ------------ Xbox controllers are already supported, but xboxdrv can solve some compatibility issues Enable xboxdrv driver, disable this if you enabled ps3 controllers (0,1)

controllers.xboxdrv.enabled=0

Set the amount of controllers to use with xboxdrv (0..4)

controllers.xboxdrv.nbcontrols=2