Using ThreadPool to connect to multiple TCP servers simultaneously - vb.net

Question

Imports System.IO
Imports System.Threading
Imports System.Net.Sockets
Imports System.Text
Module Module1
<MTAThread()>
Sub Main()
Dim maxthreads As Integer = 10
ThreadPool.SetMaxThreads(maxthreads, maxthreads)
Dim serverlist() As String = File.ReadAllLines("final.txt")
Dim servernum As New CountdownEvent(serverlist.GetUpperBound(0) + 1)
For Each a In serverlist
Dim args(1) As Object
args(0) = a
args(1) = servernum
ThreadPool.QueueUserWorkItem(New WaitCallback(AddressOf ping), args)
Next
servernum.Wait()
Console.ReadLine()
End Sub
Public Sub ping(ByVal server() As Object)
Dim serverinfo() As String = Split(server(0), ",")
Dim socketclient As New TcpClient
Console.WriteLine(serverinfo(0))
Try
socketclient.Connect(serverinfo(0), serverinfo(1))
Catch ex As Exception
If socketclient.Connected = False Then
Throw New Exception("Server Offline")
Else
Throw New Exception("Unknown Error Occured")
End If
End Try
Dim stream As NetworkStream = socketclient.GetStream
stream.ReadTimeout = 1000
stream.WriteTimeout = 1000
Dim sendBytes As [Byte]() = {&HFE}
stream.Write(sendBytes, 0, sendBytes.Length)
Dim bytes(421) As Byte
stream.Read(bytes, 0, CInt(421))
socketclient.Close()
Dim trimbytes(bytes.Length - 3) As Byte
Array.Copy(bytes, 3, trimbytes, 0, bytes.Length - 3)
Dim returndata As String = Encoding.BigEndianUnicode.GetString(trimbytes)
Dim sb As New System.Text.StringBuilder
For i As Integer = 1 To 241 Step 2
If trimbytes(i) <> 0 Then
sb.Append(ChrW(BitConverter.ToInt16(trimbytes, i)))
End If
Next i
Dim message() As String = sb.ToString.Split("§")
'Write processed server information to the console
Console.WriteLine("Received -->" & message(1) & " " & message(2) & " | " & serverinfo(0))
server(1).signal()
End Sub
End Module
Above is my code, what I basically want to do is to get two (or more) ips from the text file, connect to both of them via TCP on two different threads and get the responses from the servers.
Now, the problem here is that; for whatever reason one of the two servers get a response but the other doesn't. I've made sure both of the servers are online and accepting connections. I've also tried having the same server on both lines of the text file so that the same ip is being used on both threads but this doesn't work either. Even when the two ips are the same, one gets a response but not the other; which must mean I'm doing something horribly wrong.
When I use one server rather than 1+ everything works perfectly and I get the response I'm looking for, anything more than 1 and it looks like the first thread that runs produces the response but not anything that runs later. Any help will be appreciated.
I have also tried using Paarallel.For but ended up running into the same issue.
Parallel.ForEach(serverlist, _
Sub(currentElement)
ping(currentElement)
End Sub)