Question Working Unity scoreboard system?

Hi All,

I'm trying to create a simple scoreboard for a VR tennis game i'm making using unity and the XR Interaction Toolkit, The scoreboard is supposed to just go up by 1 whenever the racket hits the ball (These are thrown automatically). Every approach I've taken has either thrown an error or hasn't changed the number on the scoreboard.

What I have right now is basically:

The tennis racket script:

Code (CSharp):

1. public class TennisRacket : MonoBehaviour
2. {
3.     //Scoreboard scoreBoard;
4.     public GameObject scoreText;
5.     public int theScore;
6.  
7.     UI_Manager _uIManager;
8.  
9.     void Awake()
10.     {
11.  
12.     }
13.  
14.     private void OnCollisionEnter(Collision other)
15.     {
16.         if (other.collider.tag == "Ball")
17.         {
18.             _uIManager.AddScore(5);
19.         }
20.     }
21. }
22.  

Scoreboard script held on a separate UI_Manager gameobject:

Code (CSharp):

1. //Variable for Score Text
2.     [SerializeField]
3.     private Text _scoreText;
4.  
5.     //Variable for Score Number
6.     [SerializeField]
7.     private int _score;
8.  
9.     // Start is called before the first frame update
10.     void Start()
11.     {
12.         //Score set to 0 when started
13.         _scoreText.text = "S" + 0;
14.     }
15.  
16.     public void AddScore(int _killPoint)
17.     {
18.         //Add EnemyKillPoint to the score
19.         _score += _killPoint;
20.         //Update ScoreText to match the score
21.         _scoreText.text = "Score " + _score.ToString();
22.     }

I've tried so many variations of this to no avail, as far as I can tell it's something to do with the colliders but I can't be sure. The one above throws no errors but doesn't affect the _score int at all.

Has anyone else tried something similar?
Thanks in advance.