Failed to load PDF document after calling service

I have a Service that generates a PDF and returns the bytes of it:

The Service when run on the web returns this:

<?xml version="1.0" encoding="UTF-8"?>
<base64Binary xmlns="http://...com/">JVBERi0xLjMKJcfsj6IKNSAwIG9iago8PC9MZW5ndGggNiAwIFIvRmlsdGVyIC9GbGF0ZURlY29kZT4+CnN0cmVhbQp4nK2VXW+bMBSGlRgCgQhoCSWN083dh7RNKvUXBt9O2w9oFWk33FXaqmlkSvb...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</base64Binary>

On another page I call this service and then I'll make a response to download the pdf:

<%
If Len(request("ID")) > 0 Then
    ID = request("ID")
Else
    ID = -1
End If

if len(Request("IDMercado"))>0 then
    IDMercado = request("IDMercado")
else
    IDMercado = "PT"
end if 

If ID <> -1 Then

Set objRequest = Server.createobject("MSXML2.XMLHTTP")

WebserviceUrl="http://linkparaoserviço..."
Method = "GenerateCertificado" 
Parameters = "ID=" & ID & "&IDMercado=" & IDMercado

With objRequest
    .open "GET", WebserviceUrl & "/" & Method & "?" & Parameters, False
    .setRequestHeader "Content-Type", "charset=utf-8"
    .setRequestHeader "SOAPAction",  WebserviceUrl & "/" & Method
    .send
End With 

PDF = objRequest.responseBody

Response.Clear
Response.ContentType = "application/pdf"
Response.AddHeader "Content-Disposition", "attachment; filename= Certificado " & ID & ".pdf"
Response.CacheControl = "no-cache, no-store, must-revalidate"
Response.BinaryWrite PDF
Response.End

End If

window.close

%>

However, when the download is done when trying to open the PDF the following error appears:

  

Failed to Load PDF Document

What am I doing wrong?