cdc.nicusa.com has no MX records.
Question and response
Question
dig cdc.nicusa.com. MX
Answer
The response has no answer records.
Authority
cdc.nicusa.com. 300 SOA ns-1.nicusa.com. dnsadministrator.egov.com. 2025092901 300 300 2592000 300
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0