IgLou is rejecting your email because you are attempting to send an email through our mail servers, but our mail server cannot determine whether or not you are an IgLou customer.
SMTP Authentication is a way for you to identify yourself to IgLou's mail server when you are connecting to the Internet through another ISP.
Without using SMTP Authentication, our mail server has no way to identify you and your email is being rejected.
If you are an IgLou customer, please read our help article about enabling SMTP Authentication.
If you are not an IgLou customer, your mail server may be misconfigured and/or is sending your message to the wrong IP address. Please ask your ISP or email administrator for assistance in determining why the MX records for the recipient's domain name are not being processed correctly.