Public Function IsValidEmailAddress(ByVal strEmail As String, Optional ByRef sReason As String) As Boolean

On Error GoTo IsValidEmailAddress_Err

    Dim strEmailAdr As Variant
    Dim sEmail As String
    Dim i As Integer

    'cas if the string ends with only ;
    If InStrRev(strEmail, ";") = Len(strEmail) Then strEmail = Left(strEmail, Len(strEmail) - 1)
    strEmailAdr = Strings.Split(strEmail, ";")
    For i = LBound(strEmailAdr) To UBound(strEmailAdr)
        sEmail = LCase(Trim(CStr(strEmailAdr(i))))
        'sEmail = LCase(Trim(sEmail))
        IsValidEmailAddress = False
        If Len(sEmail) < 7 Then '-- Is a@b.com a valid email address?
           sReason = sEmail & " : Too short!"
        ElseIf sEmail Like "*[!0-9a-z@._+-]*" Then
           '-- not sure about these characters: ! $ & ` ' * / \ = ? ^ | # &#37; { } ~
           '   if required, add in to the above string after letter z and before the last hyphen -
           sReason = sEmail & " : Invalid character in email!"
        ElseIf Not sEmail Like "*@*.*" Then
           sReason = sEmail & " : Missing the @ or .!"
        ElseIf sEmail Like "*@*@*" Then
           sReason = sEmail & " : Too many @!"
        ElseIf sEmail Like "[@.]*" Or sEmail Like "*[@.]" _
           Or sEmail Like "*..*" Or Not sEmail Like "?*@?*.*?" Then
           sReason = sEmail & " : Invalid format!"
        Else
           Dim n As Integer
           n = Len(sEmail) - InStrRev(sEmail, ".")
           If n > 3 Then
              sReason = sEmail & " : Suffix too long!"
           ElseIf n < 2 Then
              sReason = sEmail & " : Suffix too short!"
           Else
              sReason = Empty
              IsValidEmailAddress = True
           End If
        End If
    Next i

  Exit Function
IsValidEmailAddress_Err:
  MsgBox "PublicFonctions.IsValidEmailAddress : " & vbCrLf & _
         "Error " & Err.Number & " " & Err.Description
  On Error GoTo 0
End Function