MSXML2.XMLHTTP send method works with early binding, fails with late binding

Question

The code below works. But if I comment out the line Dim objRequest As MSXML2.XMLHTTP and uncomment the line Dim objRequest As Object it fails with

Answer 1

If you use the Dim objRequest As Object then you would need to code:
Set objRequest = CreateObject("MSXML2.XMLHTTP")

Answer 2

I realise this is nearly identical to the code from Tomalek above (all credit due to you!), but this question helped me towards a full solution to a problem I had (Excel submitting to PHP server, then dealing with response)...so in case this is of any help to anyone else:

Sub Button1_Click2()

Dim objXMLSendDoc As Object
Set objXMLSendDoc = New MSXML2.DOMDocument
objXMLSendDoc.async = False
Dim myxml As String
myxml = "<?xml version='1.0'?><Request>Do Something</Request>"
If Not objXMLSendDoc.LoadXML(myxml) Then
    Err.Raise objXMLSendDoc.parseError.ErrorCode, , objXMLSendDoc.parseError.reason
End If

Dim objRequest As MSXML2.XMLHTTP
Set objRequest = New MSXML2.XMLHTTP
With objRequest
    .Open "POST", "http://localhost/SISADraftCalcs/Test2.php", False
    .setRequestHeader "Content-Type", "application/xml;charset=UTF-16"
    .setRequestHeader "Cache-Control", "no-cache"
    .send objXMLSendDoc
End With

Dim objXMLDoc As MSXML2.DOMDocument
Set objXMLDoc = objRequest.responseXML
If objXMLDoc.XML = "" Then
    objXMLDoc.LoadXML objRequest.responseText
    If objXMLDoc.parseError.ErrorCode <> 0 Then
        MsgBox objXMLDoc.parseError.reason
    End If
End If

Dim rootNode As IXMLDOMElement
Set rootNode = objXMLDoc.DocumentElement

MsgBox rootNode.SelectNodes("text").Item(0).text

End Sub

Answer 3

For some reason, this works:

Dim strPostData As String
Dim objRequest As Object

strPostData = "api_id=" & strApiId & "&user=" & strUserName & "&password=" & strPassword

Set objRequest = New MSXML2.XMLHTTP
With objRequest
  .Open "POST", "https://api.clickatell.com/http/auth", False
  .setRequestHeader "Content-Type", "application/x-www-form-urlencoded"
  .send (strPostData)
   GetSessionId = .responseText
End With

Instead of building the URL-encoded strPostData via string concatenation, it's strongly advisable to use a URL encoding function:

strPostData = "api_id=" & URLEncode(strApiId) & _
              "&user=" & URLEncode(strUserName) & _
              "&password=" & URLEncode(strPassword)

A couple of choices for a URLEncode() function in VBA are in this thread: How can I URL encode a string in Excel VBA?