You have attempt to send out an email and failed with the following error: 550 Access denied - Invalid HELO name
Double check your email setting to ensure the following settings has been made.
Microsoft Outlook
1. From the Menu Bar, Click Tools then Click E-mail Accounts
2. Select "View or change existing e-mail accounts" then Click "Next" or Accounts if using outlook 2007.
3. Double click your Email account to open it's properties.
4. Click "More settings"
5. Select "Outgoing Server" tab
6. Tick "My outgoing server (SMTP) requires authentication"
7. Select "Use same settings as my incoming email server"
8. Click "Ok"
9. Click "Next"
10. Click "Finish"
Once you have completed the above mentioned steps, close your Outlook and try sending again.