Error sending email from VBScript

When running the following script I get the errors -2147220975 and Transport code error: 0x80040217

on error resume next

Const schema   = "http://schemas.microsoft.com/cdo/configuration/"
Const cdoBasic = 1
Const cdoSendUsingPort = 2
Dim oMsg, oConf

Set oMsg      = CreateObject("CDO.Message")
oMsg.From     = "tom.watt.vulpes@gmail.com"  
oMsg.To       = "tom.watt.vulpes@gmail.com"    
oMsg.Subject  = "Test from VBScript"
oMsg.TextBody = "If you can read this, the script worked!"
objMsg.AddAttachment "C:\BLA_BLA.txt"

Set oConf = oMsg.Configuration
oConf.Fields(schema & "smtpserver")       = "smtp.gmail.com" 
oConf.Fields(schema & "smtpserverport")   = 465              
oConf.Fields(schema & "sendusing")        = cdoSendUsingPort
oConf.Fields(schema & "smtpauthenticate") = cdoBasic         
oConf.Fields(schema & "smtpusessl")       = True             
oConf.Fields(schema & "sendusername")     = "tom.watt.vulpes@gmail.com" 
oConf.Fields(schema & "sendpassword")     = "PASSWORD"      
oConf.Fields.Update()

oMsg.Send()


If Err Then
    resultMessage = "ERROR " & Err.Number & ": " & Err.Description
    Err.Clear()
Else
    resultMessage = "Message sent ok"
End If

Wscript.echo(resultMessage)

I've tried countless scripts from the internet but none of them seem to work. What am I doing wrong? Thanks, Tom

EDIT: I am running Windows 10

Transport code error: 0x80040217 can be a few different things depending on the situation. The links below should guide you in the right direction...

Overflowing Stack

MSDN