OnReceivedBroadcast not being called with Network Discovery

I have written the following code for automatically connecting to a LAN game. A pair of buttons call startLanHost and startClient. When running two builds of the game OnReceivedBroadcast is never called by a client. Is my code not written correctly?

 public class NetworkConnector : NetworkDiscovery {
     
 
     public NetworkManager networkManger;
     public bool gameFound;
     public bool lookingForGame;
     public string networkAddress;
     // Use this for initialization
     void Start () {
     
     }
     
     // Update is called once per frame
     void Update ()
     {
         if (lookingForGame && gameFound)
         {
             networkManger.StartClient();
         }
     }
     public void startLanHost()
     {
         Initialize();
         networkManger.StartHost();
         StartAsServer();
     }
     public void startClient()
     {
         Initialize();
         StartAsClient();
         lookingForGame = true;
     }
     public override void OnReceivedBroadcast(string fromAddress, string data)
     {
         Debug.Log("Revcieved broadcast");
         networkManger.networkAddress = fromAddress;
         gameFound = true;
     }
 }