Issue with Collision

c#
I want to be able to detect when an there an attack hits another object. There is nothing being detected when any collisions happen. I would like it to only be for a specific trigger but at the moment just getting collisions would be good.

Code (CSharp):

1.     void OnCollisionEnter(Collision collisionInfo)
2.     {
3.         if (collisionInfo.collider.tag == "Player")
4.         {
5.             Debug.Log("Collision");
6.         }
7.     }

I have also tried with this:

Code (CSharp):

1.     void OnCollisionEnter(Collision collisionInfo)
2.     {
3.  
4.             Debug.Log("Collision");
5.  
6.     }

 

For a start it should be...

if(collisionInfo.gameObject.tag == "Player") {