Assuming it is working in editor the most hazardous line is 37-th.
As I admit you are checking MeshContainer for validity before work, but forgot about AnimBlueprint. There is a little ambiguity with Android (as I can see from log it’s an Android app) that object finders can not work sometimes. I don’t know why and when, but it is happening.
Solution to avoid this is possibly very simple, but you are need to create blueprint derived from this character.
You can create TSubclassOf<> to declare class template as class variable.
What I mean is that you need to assign template variables through editor and use them in class constructor.
Like for skeletal mesh you need to declare in your character class field:
UPROPERTY(BlueprintReadWrite, EditAnywhere, Category = "character category")
TSubclassOf<USkeletalMesh> MeshTemplate;
Create this mesh and assign to character’s mesh.
Same for AnimBlueprint, and it’s not recommended to use pure blueprint class, better to at least derive it from something and get it as type it’s really appears to be. E.g. if we created actor blueprint, then we find this object supposing it’s AActor, not UBlueprint.
И вопрос необходимо расписывать с максимумом известной информации, я, например, не понял в какой момент произошло падение. Судя по названию данного вапроса, я даже позореваю, что я зря на английском написал, но это так, для публики.