Can i get help with this error?

I am getting an error in the survival Shooter tutorial part 6 and it is triggered whenever i enter play mode something in the script is not working the way it should be and i think it has something to do with the enemy. This is the error i am getting

NullReferenceException: Object reference not set to an instance of an object
PlayerHealth.Update () (at Assets/Scripts/Player/PlayerHealth.cs:44)

Any help with this? Please and thank you.

In the inspector find the script and have fun filling in the values!

        -For further asssistance plz comment