Domain shares an MX record (mx2.zoho.com) for a mail exchange which will not accept mail to the administrator

Domain shares an MX record (mx2.zoho.com) for a mail exchange which will not accept mail to the administrator

I've found my domain on a blacklist ( http://rfc-clueless.org/) due to the following: "Domain shares an MX record (mx2.zoho.com) for a mail exchange which will not accept mail to the administrator."

I'm not sure what that means, but the list states that it is "[...] not a spam list. Each of our curated lists track compliance with specific requirements of RFCs (with the exception of the elitist list)."

Can I configure something to remedy this, or does Zoho simply not follow the requirements of RFC?