E-mail Trouble Shooting
How can I solve RFC2821 4.1.1.1 Error in e-mail client software?
When you are trying to send mail, the client software receives the "Access denied - Invalid HELO name (See RFC2821 4.1.1.1)" Error. This is often caused by not having SMTP Authentication turned on. Please make sure that you have SMTP
Authentication turned on in your email client and try sending the email again.