Had the same problem when i updated my S2 to Nougat. you have to go to Settings>Apps the click the 3 dots top right to select Default Apps then select "Ask before setting defaults apps" .. but before that you may have to clear defaults for Litchi or DJI Go..Now you should get a propmt asking...
Running 8" Tab S2 710 on Lollipop 5.1.1. with zero issues.. worked out of the box.. turned off automatic updates to avoid Marshmallow issues using Litchi and DJI GO on the same device..
Using this for my Sammy S2 8" and its a good fit.. nice and tidy, only for connectivity and not charging. Using the supplied cable for charging the remote..
https://www.amazon.com/gp/product/B01LZFKVDP/ref=oh_aui_detailpage_o00_s01?ie=UTF8&psc=1