无法使用system.net.mail从VB表单发送邮件

我们公司拥有一个呼叫中心，该PC被锁定（无法访问互联网，电子邮件，办公应用程序），并且需要他们能够从自己的计算机上记录支持记录。

我创建了一个VB Windows窗体应用程序，该应用程序从用户那里获取一些信息（名称，电子邮件，扩展名，主题和问题描述）以及从WMI收集的系统信息。

我打算通过电子邮件将所有这些信息发送到我们的服务台，sys信息将使我们能够识别硬件问题等。

但是，当尝试发送邮件时。它只是不起作用。

我们有一个smtp中继，它允许匿名电子邮件中继，并且不需要用户凭据。

一旦我获得了基本的测试邮件，我将开始使用从用户那里获得的信息来填充邮件。但是，该邮件当前引发异常，根本不发送。

注意当涉及到VB和.net时，我是一个绝对的初学者，因为我来自linux / php背景

下面是我的代码：

Imports System.Management
Imports System.Management.Instrumentation
Imports System.Net.Mail

Public Class Form1

    Private Property strComputer As String
    Private Property objWMIService As Object
    Private Property colItems As Object
    Private Property colComputers As Object
    Private Property strComputerRole As String
    Private Property colDisks As Object
    Private Property colOperatingSystems As Object
    Private Property IPConfigSet As Object

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        Dim response As MsgBoxResult
        response = MsgBox("Are you sure you want to exit?", MsgBoxStyle.Question + MsgBoxStyle.YesNo, "Confirm")
        If response = MsgBoxResult.Yes Then
            Me.Dispose()
        ElseIf response = MsgBoxResult.No Then
            Exit Sub
        End If
    End Sub

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

        Dim strName As String
        Dim strDept As String
        Dim strEmail As String
        Dim strExt As String
        Dim strDesc As String
        Dim strAffect As String
        Dim strSubject As String

        strName = TextBox1.Text
        strDept = TextBox2.Text
        strEmail = TextBox3.Text
        strExt = TextBox4.Text
        strSubject = TextBox6.Text
        strDesc = RichTextBox1.Text
        strAffect = TextBox5.Text

        strComputer = "."
        objWMIService = GetObject("winmgmts:" _
            & "{impersonationLevel=impersonate}!\\" _
            & strComputer & "\root\cimv2")
        colItems = objWMIService.ExecQuery _
            ("Select * from Win32_ComputerSystem")
        For Each objItem In colItems
            TextBox7.Text = objItem.Name
            TextBox8.Text = objItem.Manufacturer
            TextBox9.Text = objItem.Model
            TextBox11.Text = objItem.TotalPhysicalMemory
        Next
        colComputers = objWMIService.ExecQuery _
    ("Select DomainRole from Win32_ComputerSystem")
        For Each objComputer In colComputers
            Select Case objComputer.DomainRole
                Case 0
                    strComputerRole = "Standalone Workstation"
                Case 1
                    strComputerRole = "Member Workstation"
                Case 2
                    strComputerRole = "Standalone Server"
                Case 3
                    strComputerRole = "Member Server"
                Case 4
                    strComputerRole = "Backup Domain Controller"
                Case 5
                    strComputerRole = "Primary Domain Controller"
            End Select
            TextBox10.Text = strComputerRole
        Next
        colItems = objWMIService.ExecQuery("Select * from Win32_Processor")
        For Each objItem In colItems
            TextBox12.Text = objItem.Manufacturer
            TextBox13.Text = objItem.Name
            TextBox14.Text = objItem.MaxClockSpeed & " MHz"
        Next
        colItems = objWMIService.ExecQuery("Select * from Win32_BIOS")
        For Each objItem In colItems
            TextBox15.Text = objItem.Version
            TextBox16.Text = objItem.SerialNumber
        Next
        colItems = objWMIService.ExecQuery("Select * from Win32_VideoController")
        For Each objItem In colItems
            TextBox17.Text = objItem.Name
        Next
        colDisks = objWMIService.ExecQuery("Select * from Win32_LogicalDisk where DeviceID = ""C:""")
        For Each objDisk In colDisks
            TextBox18.Text = Math.Round(objDisk.Size / 1073741824) & " GB"
            TextBox19.Text = Math.Round(objDisk.Freespace / 1073741824) & " GB"
        Next
        colOperatingSystems = objWMIService.ExecQuery("Select * from Win32_OperatingSystem")
        For Each objOperatingSystem In colOperatingSystems
            TextBox20.Text = objOperatingSystem.Caption & "  " & objOperatingSystem.Version
            TextBox21.Text = objOperatingSystem.ServicePackMajorVersion & "." & objOperatingSystem.ServicePackMinorVersion
        Next
        Dim moIP As ManagementObject

        Dim myNet = New ManagementObjectSearcher _
        ("SELECT * FROM Win32_NetworkAdapterConfiguration WHERE IPEnabled = True")

        For Each moIP In myNet.Get
            ' Eg: Display IP address in Message Box
            TextBox22.Text = moIP("IPAddress")(0)
        Next

        Dim mail As New MailMessage()
        mail.To.Add("[email protected]")
        mail.From = New MailAddress(strEmail)

        Dim smtp As New SmtpClient()
        smtp.Host = "relay.company.local"
        smtp.EnableSsl = False

        mail.Subject = strSubject
        mail.Body = strDesc
        smtp.Send(mail)

    End Sub

    Private Function Wscript() As Object
        Throw New NotImplementedException
    End Function

    Private Function IsNull(p1 As Object) As Boolean
        Throw New NotImplementedException
    End Function


End Class

更新：下面是一个例外

An unhandled exception of type 'System.Net.Mail.SmtpException' occurred in System.dll

Additional information: Service not available, closing transmission channel. The server response was: 4.3.2 Service not available, closing transmission channel