PDCDNS.vzbi.com has no CNAME records.
Question and response
Question
dig PDCDNS.vzbi.com. NS
Answer
The response has no answer records.
Authority
vzbi.com. 427 SOA omzdns9.verizon.com. domainlegalcontact\.verizon.com. 1307524 1200 960 604800 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0