I've got the Galaxy Tab S2 9.7". I had the same problem. Unfortunately Litchi blames it on Marshmallow. The problem is Litchi will not connect as long as DJI Go is installed. You can uninstall it and Litchi will work... but who the heck wants to do that?!?! I ,like you, need both apps. I found a way around it, Create a 2nd user with only Litchi installed on it. You can easily switch between users then all you have to do is unplug and replug the USB and it will connect. That was my experience anyway. Hopefully Litchi finds a way around this soon.