mail0.use2001.mcdlv.net has no CNAME records.
Question and response
Question
dig mail0.use2001.mcdlv.net. NS
Answer
The response has no answer records.
Authority
mcdlv.net. 8814 SOA pdns177.ultradns.com. dev.mailchimp.com. 2012103790 86400 86400 86400 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0