UE4 Animated Object turns black

Hi to everyone.

I am working on a train door system simulation.
When I import a door for example, I place it into the scene all works fine.
But when I create a matinee and pick the door to animate it, the door becomes black or gray.
Although there is no overlap with every object I animate, it changes color.
In the images I have uploaded you can see on the left side the not animated door, on right side the animated door.
How can I fix this ?