Nighthawk MR1100 tethered to a Wifi Ranger router

I recently purchased a Nighthawk hotspot and want to tether it to a separate router.  The router is a WiFi Ranger Spruce.  I have been using a Unite Explore and it was working just fine tethered to the router but when I connect the Nighthawk, the router senses it but cannot connect.  I turned off IP Passthrough, selected Charge + tether.  Is there something I am missing?