I have Ensim Servers, One Pro and another one Basic. When I run dnsreport on Basic server, it warns me that

WARN: One or more of your mailservers does not accept mail in the domain literal format (user@[]). Mailservers are technically required RFC1123 5.2.17 to accept mail to domain literals for any of its IP addresses. Not accepting domain literals can make it more difficult to test your mailserver, and can prevent you from receiving E-mail from people reporting problems with your mailserver. However, it is unlikely that any problems will occur if the domain literals are not accepted.

mail.nsiindia.net's postmaster@[] response:
>>> RCPT TO:<postmaster@[]>
<<< 550 5.7.1 ... Relaying denied

But on Pro I get Literals Seems working okay. I am not able to figure out how do I fix this literal issue on Basic Server.

Can anybody guide me.