Why do my server and client crash on startup?

I'm very new to Networking, so I've been trying to develop my own Server and Client to use with Unity. I of course did some copy and pasting to learn the basics, but now I'm trying to get a real grasp of how to accomplish what I am looking for. As for now, I just want to connect a client to a server(UDP), and get a confirmation that it is working before I continue.

My current issue is this: Unity crashes immediately upon running the game.

Server:

 using System;
 using System.Net;
 using System.Net.Sockets;
 using System.Text;
 
 public class Server
 {
     private const int port = 8080;
 
     public static int Main()
     {
         //bool done = false;
         UdpClient listener = new UdpClient(port);
         IPEndPoint groupEP = new IPEndPoint(IPAddress.Any, port);
         string receivedData;
         byte[] receivedBytes;
 
         try
         {
                 Console.WriteLine("Waiting for broadcast...");
                 receivedBytes = listener.Receive(ref groupEP);
 
                 Console.WriteLine("Receiving broadcast from: {0}", groupEP.ToString());
 
                 receivedData = Encoding.ASCII.GetString(receivedBytes, 0, receivedBytes.Length);
                 Console.WriteLine("Data follow\n{0}\n\n", receivedData);
         }
 
         catch (Exception e)
         {
             Console.WriteLine(e.ToString());
         }
         listener.Close();
         return 0;
     }
 }

Client:

 using System;
 using System.Net;
 using System.Net.Sockets;
 using System.Text;
 
 public class Client
 {
     public static void Main()
     {
         //Boolean done = false;
         Boolean exception_Thrown = false;
 
         Socket sending = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
 
         IPAddress sendTo = IPAddress.Parse("192.168.1.127");
 
         IPEndPoint sendEndPoint = new IPEndPoint(sendTo, 8080);
 
         Console.WriteLine("Enter text to broadcast");
         Console.WriteLine("Enter a blank line to exit the program");
 
 
         string sendText = "Success!";
         /*
         if (sendText.Length == 0)
         {
             done = true;
         }
         
         else
         {
         */
             byte[] sendBuffer = Encoding.ASCII.GetBytes(sendText);
             Console.WriteLine("Send to address: {0}, port: {1}", sendEndPoint, sendEndPoint.Port);
 
             try
             {
                 sending.SendTo(sendBuffer, sendEndPoint);
             }
 
             catch (Exception send_Exception)
             {
                 exception_Thrown = true;
                 Console.WriteLine("Exception {0}", send_Exception);
             }
 
             if (!(exception_Thrown))
             {
                 Console.WriteLine("Message has been sent to the broadcast address");
             }
 
             else
             {
                 exception_Thrown = false;
                 Console.WriteLine("The exception indicates the message was not sent");
             }
         //}
     }
 }

The script I'm going to use to call the other scripts without MonoBehaviour:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using System;
 
 public class ServerManager : MonoBehaviour
 {
     private GameObject netGameObject;
     private Server serverScript;
     private Client clientScript;
     //private float timer = 0.0f;
     //private float nextServerUpdate = 2.0f;
     //private bool runUpdate = true;
     //private bool s = false;
 
     // Start is called before the first frame update
     void Start()
     {
         netGameObject = this.gameObject;
         serverScript = new Server();
         clientScript = new Client();
         StartCoroutine(ServerUpdate(2f));
         //Server.Main();
         //Client.Main();
     }
     /*
     // Update is called once per frame
     void Update()
     {
         if (Input.GetKey(KeyCode.Y))
         {
             s = true;
         }
     }
     */
     private IEnumerator ServerUpdate(float waitTime)
     {
         while (true)
         {
             Server.Main();
             Debug.Log("Working");
             yield return new WaitForSeconds(waitTime);
         }
     }
 }
 

I've been toying with various things for a while now, and I really need some help. Things I've tested: 1. the coroutine freezes as soon as it hits Server.Main(). 2. DIY timers react the same as coroutine. 3. while(true) loop in coroutine doesn't appear to make a difference. 4. Server.Main() freezes even from start or awake, with all loops that I can find removed. 5. Client.Main() gives me the exact same problems.

Just a note: I have been avoiding Unity's built in systems (UNET and the like) because networking is something I would really like to learn to manage for myself, where I could use it outside of Unity as well.

I would really appreciate any assistance with this, thanks in advance =)