ns4.xtom.com has no CNAME records.
Question and response
Question
dig ns4.xtom.com. NS
Answer
The response has no answer records.
Authority
xtom.com. 61 SOA ns1.xtom.com. hello.xtom.com. 2026020309 3600 600 604800 180
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0