Anim Trail only rendering when pawn moves in one direction

Hello,
I´ve followed this tutorial: https://docs.unrealengine.com/latest/INT/Videos/PLZlv_N0_O1gYDLyB3LVfjYIcbBe8NqR8t/5HkghxEIXiU/

and after I´ve attached the anim trail and started the game, it became clear that the trail is only rendering when the player moves from right to left. I have attached two screenshots for a better understanding.

215526-screenshot-5.png

215527-screenshot-6.png

Okay fixed. For all people who run into the same problem: Just set the material two sided