fltr-in2.mail.dreamhost.com has no CNAME records.
Question and response
Question
dig fltr-in2.mail.dreamhost.com. NS
Answer
The response has no answer records.
Authority
dreamhost.com. 300 SOA ns1.dreamhost.com. hostmaster.dreamhost.com. 2026030900 2015 1800 1209600 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0