edgemail1.constantcontact.com has no CNAME records.
Question and response
Question
dig edgemail1.constantcontact.com. NS
Answer
The response has no answer records.
Authority
constantcontact.com. 600 SOA dns1.p01.nsone.net. hostmaster.nsone.net. 1657679378 3600 600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0