Problems with 2D Collision/Trigger

I googled alot but nothing helps. So I have to ask.

 void OnCollisionEnter2D(Collision2D collision)
 {
     Debug.Log("Collide");
 }
 void OnTriggerEnter2D(Collider2D other) {
     Debug.Log("Trigger");
 }

I use this to check if a Trigger or Collision happens. I dont want to use rigidbodys, just simple colliders. I tried colliders on both object ( In this case a projectile and a "enemy" object, projectile is extra slow because I know collisions dont work so good if its too fast). One object uses PolygonCollider2D , the other CircleCollider2D. I tried with trigger on/off on/on off/off off/on, but neither collision or trigger works.

Both Objects are on the same layer and same Z position... Any ideas?