Usb OTG , can't copy/move things onto the usb

[AC Question]

I have a Nexus 5X and got this little thing : Kingston DataTraveler microDuo 3C 16GB USB 3.0/3.1 + Type-C Flash . I am trying to use this but i can't move or copy things into the usb. However i can take things out of the usb and move them inside the phone. Any help?