For some reason, we couldn't directly figure out how to use our normal VBscript that sends emails to send emails using an ExchangeOnline/Office 365 account.   We tried all kinds of steps and it didn't work.    So we eventually decided to just configure an SMTP service on our server using IIS 6 and then having our VBScript talk to the IIS SMTP service, which then sends the emails via Office 365.

Here are the steps:

1)  Configure your IIS SMTP service using the steps in this Microsoft kbase article:

2)   Configure VBScript code as follows:

Dim strBody
strBody = "Test email "
Dim ObjSendMail
Set ObjSendMail = CreateObject("CDO.Message")
 
 'This section provides the configuration information for the remote SMTP server.
 ObjSendMail.Configuration.Fields.Item ("http://schemas.microsoft.com/cdo/configuration/sendusing") = 2 
 ObjSendMail.Configuration.Fields.Item ("http://schemas.microsoft.com/cdo/configuration/smtpserver") = "127.0.0.1"
 ObjSendMail.Configuration.Fields.Item ("http://schemas.microsoft.com/cdo/configuration/smtpserverport") = 587
 ObjSendMail.Configuration.Fields.Item ("http://schemas.microsoft.com/cdo/configuration/smtpusessl") = 0
 ObjSendMail.Configuration.Fields.Item ("http://schemas.microsoft.com/cdo/configuration/smtpconnectiontimeout") = 60
 ObjSendMail.Configuration.Fields.Item ("http://schemas.microsoft.com/cdo/configuration/smtpauthenticate") = 1

NOTE:  these next two lines are the windows user id and password that has security permissions to connect to the

IIS server:

 ObjSendMail.Configuration.Fields.Item ("http://schemas.microsoft.com/cdo/configuration/sendusername") = "userid"

 ObjSendMail.Configuration.Fields.Item ("http://schemas.microsoft.com/cdo/configuration/sendpassword") = "password"
 ObjSendMail.Configuration.Fields.Update
    
 ObjSendMail.To = "someone@email.com"
 ObjSendMail.Subject = "test email "
 ObjSendMail.From = "someone@yourorganization.com"
 
 ObjSendMail.TextBody = strBody
 ObjSendMail.Send
 Set ObjSendMail = Nothing  

3)   You have to go into the Office 365 admin portal and create a connector for the IP address of the IIS SMTP server.

Go to the Exchange Online admin center, then "mail flow" then "connectors".   You have to add a rule that allows a connection from your IIS SMTP server.