I get a lot of error messages like “501 Syntactically invalid HELO argument(s)” or “552 Syntax HELO error”. How can they be solved?
To avoid these errors, you must enter either your IP address or domain name into Domain name for HELO field in the Advanced Email Verifier settings under the Connection tab.
It is preferable that you enter your domain name instead of the IP address because not all mail servers recognize the IP in the HELO command. The domain name is the last part of the email address. For example, if you use the [email protected] email address, the domain is blabla.com.
Interested? Learn more about our Advanced Email Verifier.