This code worked for me when outlook is opened.
Code:
Set MyApp = CreateObject("Outlook.Application")
Set MyItem = MyApp.CreateItem(0) 'MailItem
With MyItem
.To = "a@a.com"
.Subject = "test"
.ReadReceiptRequested = False
.HTMLBody = "A new project has been created!"
'.display
'SendKeys "%{s}", True
'Type alt+micEnter
.Attachments.Add("c:\test1.txt")
.Send
End With