Angry bot enemy not attacking.

Hello developers, greetings. I was testing the Angry Bots project and it is pretty good for me. Whenever i add rigidbody to any 3d object(Without any other components) and select its tag and layer as player, the spider mechs and buzzer mechs attack me. But unfortunately when i am selecting a scripted character with few components, the spider mechs no more attacking. Is there any solution to make them attack me???

Thank you.