An Instantiated UI Button doesn't work; clicking does nothing.

I'm trying to make a system where the player can attach different "modules" to "nodes on their vehicle. So I want the player to be able to enter the inventory, showing all their modules, click a module they want to attach, at which point their ship is displayed, with images highlighting each available attachment node. These images will be buttons which, once clicked, attach the chosen module to that attachment point. I have a script which instantiates the buttons as children of some empty "attach point" game objects which are in turn children of the player's vehicle. So the buttons show up fine, but I can't interact with them. I click them but nothing happens. I've checked that there's an EventSystem in the hierarchy and that the buttons are set to interactable.

Here are some pictures of the component setup on the button prefab:

The code which instantiates the buttons (which is working) is

 using UnityEngine;
 using UnityEngine.UI;
 using System.Collections;
 using Assets._Custom._Scripts._Helpers;
 using Assets._Custom._Scripts._ShipScripts;
 
 namespace Assets._Custom._Scripts._GUIScripts
 {
     public class ShipImageDisplay : MonoBehaviour 
     {
         private GameObject shipObject;
         private ShipData playerShipInfo;
         public GameObject shipDisplayPoint;
 
         public GameObject nodeImagePrefab;    //the prefab that will be instantiated at each available attachment node.
         public Module chosenModule;
 
         private void OnEnable()
         {
             shipObject = GameObject.Find("PlayerShip001");
             playerShipInfo = shipObject.GetComponent<Ship>().data;
             int numberOfAvailableNodes = playerShipInfo.shipAvailableAttachPoints.GetLength(0);
             Debug.Log (numberOfAvailableNodes);
 
             for (int i = 0; i < numberOfAvailableNodes; i++)
             {
                 GameObject nodeDisplay = Instantiate(nodeImagePrefab) as GameObject;
                 nodeDisplay.transform.position = playerShipInfo.shipAvailableAttachPoints[i].position;
                 nodeDisplay.transform.SetParent(playerShipInfo.shipAvailableAttachPoints[i], false);
                 nodeDisplay.GetComponentInChildren<NodeBtnScript>().nodeIndex = i;
                 nodeDisplay.GetComponentInChildren<NodeBtnScript>().module = chosenModule;
             }
 
             Messenger.Broadcast(Broadcasters.ModuleChosenEvent.ToString());
         }
     }
 }

The code on the NodeBtn script is

 using System;
 using System.Collections;
 using Assets._Custom._Scripts._ShipScripts;
 using Assets._Custom._Scripts._Helpers;
 
 namespace Assets._Custom._Scripts._GUIScripts
 {
     public class NodeBtnScript : MonoBehaviour 
     {
         public int nodeIndex;    //the index  (in the available nodes array) of the node this image is highlighting.
         public Module module;    //the module we're attaching.
 
         private Button thisBtn;
 
         private void Awake()
         {
             thisBtn = GetComponent<Button>();
             thisBtn.onClick.AddListener(Click);
         }
 
         public void Click()
         {
             /*For some reason, Messenger broadcasting was messing up, so I'll try to fix that later on.*/
             Messenger<Module, int>.Broadcast(Broadcasters.ModuleAttachEvent.ToString(), module, nodeIndex);
 
             Debug.Log ("Node chosen");
         }
     }
 }

Any advice and help you could provide would be much appreciated.