mail.concursolutions.com has no CNAME records.
Question and response
Question
dig mail.concursolutions.com. NS
Answer
The response has no answer records.
Authority
concursolutions.com. 27 SOA ns0.concur.net. eoperator.concur.com. 2019082630 10800 3600 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0