We have upgraded to Play 2.7.0 recently and use play2-reactivemongo version 0.16.2 with reactivemongo 0.16.3. We use reactivemongo-shaded-native but also tried
reactivemongo-shaded-native
Have you tried: http://reactivemongo.org/releases/0.1x/documentation/tutorial/connect-database.html#netty-native
Have had a similair error and a colleague suggested the above. Seems to be working for us.