Galaxy S6 USB Tether to Router

[S6Tether]

Hi, I'm trying to use my Sprint Galaxy S6 to tether with my ASUS RT-AC68U router. I got my MSL number and turned on the hotspot/tethering options, and they work (I can use the wifi hotspot and USB tether with my laptop). However, when I plug in the USB to the router and have the router attempt to connect, it turns off the USB tether on the S6. This doesn't happen with my Verizon HTC M8, with the same router. Any thoughts or ideas why?