ncrx.gov has no MX records.
Question and response
Question
dig ncrx.gov. MX
Answer
The response has no answer records.
Authority
gov. 300 SOA a.ns.gov. dns.cloudflare.com. 1772158202 3600 900 604800 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0