How to remove [External:] from subjects coming in - Office 365

The code i am trying to run as a script:

Const CLASS_NAME = "SendAndReceive"

Private WithEvents olkApp As Outlook.Application
Private bolSend As Boolean, bolReceive As Boolean

Private Sub Class_Initialize()
bolSend = True
bolReceive = True
Set olkApp = Outlook.Application
End Sub

Private Sub Class_Terminate()
Set olkApp = Nothing
End Sub

Private Sub olkApp_ItemSend(ByVal Item As Object, Cancel As Boolean)
If (Left(Item.Subject, 4) = "FW: ") Or (Left(Item.Subject, 4) = "RE:") Then
Item.Subject = Mid(Item.Subject, 5)
Item.Save
Else
If Left(Item.Subject, 5) = "Fwd: " Then
Item.Subject = Mid(Item.Subject, 6)
Item.Save
End If
End If
End Sub

Private Sub olkApp_NewMailEx(ByVal EntryIDCollection As String)
Dim arrEID As Variant, varEID As Variant, olkItm As Object
arrEID = Split(EntryIDCollection, ",")
For Each varEID In arrEID
Set olkItm = Outlook.Session.GetItemFromID(varEID)
If olkItm.Class = olMail Then
Select Case Left(olkItm.Subject, 4)
Case "FW: ", "RE: ", "SV: "
olkItm.Subject = Mid(olkItm.Subject, 5)
olkItm.Save
End Select
End If
Next
Set olkItm = Nothing
End Sub

Public Sub ToggleSend()
bolSend = Not bolSend
MsgBox "The process of removing RE: and FW: on sent messages has been turned " & IIf(bolSend, "'On'", "'Off'"), vbInformation + vbOKOnly, CLASS_NAME
End Sub

Public Sub ToggleReceive()
bolReceive = Not bolReceive
MsgBox "The process of removing 'RE:', 'FW:', and 'Fwd:' on received messages has been turned " & IIf(bolReceive, "'On'", "'Off'"), vbInformation + vbOKOnly, CLASS_NAME
End Sub