Thread does not read change in boolean

Hello! I am working on a multiplayer game, using the lidgren library for networking.

I am currently having issues with a my function that reads messages sent from my server. The function looks like this: public class Client / code omitted /

 public void ReadMessage()
     {   //Read Messages
         while (running)
         {
             Debug.Log("InREAD");
            //wClient is a NetClient (lidgren library)
             NetIncomingMessage msg;
             while ((msg = wClient.ReadMessage()) != null)
             {
                 
                 switch (msg.MessageType)
                 {
                     case NetIncomingMessageType.Data:
                     
                         if (msg.ReadString().Contains("Position"))
                         {
                             Debug.Log("Hej");
                             /*string temp = msg.ReadString();
                         string[] Parts = temp.Split(" ");
                         
                         int x = int.Parse(Parts [1]);
                         int y = int.Parse(Parts [2]);
                         int z = int.Parse(Parts [3]);*/
                         
                         
                             //set player position to xyz values below
                         } else if (msg.ReadString().Contains("Instantiate"))
                         {
                             Debug.Log("Instantiate");
                             /* string temp = msg.ReadString();
                             string[] Parts = temp.Split(" ");*/
                         
                         }
                         break;
                     
                 }
             }
 
         }
     }

as you can see, there is a while-loop that runs when the bool running is true (and yes i am setting it as true when declaring.).

Now, in my GUI class where the button for connecting is etc, I have a function call to On ApplicationQuit which looks like this:

     void OnApplicationQuit()
     {
         client.running = false;
         client.Disconnect();
         Debug.Log(client.running);
         Debug.Log("Bye");
     }

however, the change of running doesn't reach the thread (I believe the thread is running on a cached version of the variable?). So my question is, how do i make the while-loop stop when the program is closed? (Ive tried calling on the .Abort() function on the thread in the OnApplicationQuit(), but it doesn't work either.

Also, i know its not very efficient to send strings over a network unless you need to (so no need telling me about that!)