c# – Unity: Cannot access TMP_Text object from script in gameobject

I’m trying to set the color property of a TMP_Text object but keep getting Object reference not set to instance of an object error. Setup is as follows;

1. I have a Canvas (game hud) that has 6 TMP_Text objects in it for stats. 3 are static text and 3 are to be updated from other scripts.

2. I have a gameobject that will be moving and a script that will change the text color of one of the values in the hud based on the game object velocity exceeding a fixed limit.

   using System.Collections.Generic;
   using UnityEngine;
   using TMPro;
   
   public class shipCollision : MonoBehaviour {
     // The TMP_Text object is dragged into the inspector before runtime
     public TMP_Text txtVertVelVal;
   
      private void Update() {
        landerRb = lander.GetComponent<Rigidbody>();
   
        Vector3 landerVelocity = landerRb.velocity;
        if(landerVelocity.y > 3f) {
          txtVertVelVal.color = Color.red;
        } else {
          txtVertVelVal.color = Color.green;
        }
   }
   
   

So, is this failing to because I am not referencing the parent Canvas maybe?