Promt Warning List External Users, on VB Script to checks for external users

[charli1]

Still stuck at this line,

domain = Mid(strRecipientAddress, InStr(strRecipientAddress, "@"))

following the full code.

Private Sub Application_ItemSend(ByVal Item As Object, Cancel As Boolean)
    Dim objMail As Outlook.MailItem
    Dim objRecipients As Outlook.Recipients
    Dim i As Long
    Dim strRecipientAddress As String
    Dim strPrompt As String
	Dim Address As String
	Dim domain As String
	
    If TypeOf Item Is MailItem Then
       Set objMail = Item
       Set objRecipients = objMail.Recipients
 
       For i = 1 To objRecipients.Count     ' no need to step backwards as you are not removing items from the collection
			strRecipientAddress = objRecipients.Item(i).Address
			domain = Mid(strRecipientAddress, InStr(strRecipientAddress, "@"))
			Select Case domain
			Case "@my1Domain.com", "@my2Domain.com", "@my3Domain.com", "@my4Domain.com", "@my4Domain.com"
			Case Else:     rejects = rejects & vbNewLine & strRecipientAddress
			End Select

		Next
         
         If rejects <> "" Then
          strPrompt = "This email will be sent outside of the company to:" & vbNewLine & strRecipientAddress & vbNewLine & "Please check recipient address." & vbNewLine & vbNewLine & "Do you still wish to send?"
            If MsgBox(strPrompt, vbYesNo + vbExclamation + vbMsgBoxSetForeground, "Check Address") = vbNo Then
            Cancel = True
         End If
        End If
    End If
End Sub