rp.entregaemail.com has no CNAME records.
Question and response
Question
dig rp.entregaemail.com. NS
Answer
The response has no answer records.
Authority
entregaemail.com. 1800 SOA kim.ns.cloudflare.com. dns.cloudflare.com. 2398296022 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0