mx04.lexisnexis.com has no CNAME records.
Question and response
Question
dig mx04.lexisnexis.com. NS
Answer
The response has no answer records.
Authority
lexisnexis.com. 900 SOA spn5061.telecom.regn.net. hostmaster.lexisnexis.com. 9653 3600 900 2419200 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0