Re: Can anyone tell me what's wrong with this domain?

SL> deferral:sender_was_rejected./Remote_host_said:_450_4.4.1_Sender_domain_not_foun d_in_DNS/

Now show us the part of the log that tells us what the envelope
sender mailbox on that message actually _was_, so that we can
perform the DNS lookups ourselves on the relevant domain name
and see whether there is in fact a problem.

Don't just assume that the domain name that the SMTP Relay server
doesn't like is "lists.literacytent.com.". _Show_ us that the domain
name that it doesn't like is in fact "lists.literacytent.com.".

SL> some servers still report the "not in DNS" issue.

Did you wait 1 day (the TTL of the prior empty responses) before
considering this to be a problem ?