550 Access Denied Invalid HELO From VBS Script

I was using CDO in a VBS script to send a e-mail with a free disk space report on it, when I tried the script on any PC I had here it worked ok, yet when I tried it on site it didnt work I kept getting the following error.

550 access denied – invalid HELO

At first I thought maybe port 25 was been blocked but it was not, so then I was think maybe the PC’s are missing some strange Windows update that my PC’s have, but they didnt.  After much looking on Google all I could see was a reference to this error in Outlook and other mail clients, well I am using CDO in a VBS script so why should that matter you may ask, then the penny dropped, my PC’s here all have Outlook on setup with mail accounts, the PC’s on site I was trying this script on didnt have Outlook etc. Thats all I can think the issue was.  The way around it is to add authentication to the VBS script as follows, as shown in red.

Const cdoAnonymous = 0 ‘Do not authenticate
Const cdoBasic = 1 ‘basic (clear-text) authentication
Sub SendMail(Sender, Recipient, Subject, Message)
Set objMessage = CreateObject(“CDO.Message”)
objMessage.Subject = Subject
objMessage.From = Sender
objMessage.To = Recipient
objMessage.TextBody = Message

Tested and then, it worked.