gateway1a.dhl.com has no CNAME records.
Question and response
Question
dig gateway1a.dhl.com. NS
Answer
The response has no answer records.
Authority
dhl.com. 33 SOA ns4.dhl.com. netmaster.dhl.com. 2016118558 10800 3600 604800 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0