Can't save a Map because of ActorSequence in a BlueprintActor

Hello i’m a student in Game design, i’m currently learning UnrealEngine 4 and i can’t save my map because of this error :
-Graph is linked to external private object unknown blueprint

After some trials and error, i identified that the source of the problem is the actor sequence that i put as a component of my Blueprint actor. Because i wanted to animate my actor.
And after i looked at the chain of reference is this :

Blueprint/B_door.B_door_C:ActorSequence_GEN_VARIABLE.Sequence.MovieScene.NodeGroupCollection.MovieSceneNodeGroup_0 (NodeGroups)

How do i solve this ?

And sorry if i didn’t put any image i don’t know to how to put them in here, it’s my first time here.