ns1.serverlet.com has no CNAME records.
Question and response
Question
dig ns1.serverlet.com. NS
Answer
The response has no answer records.
Authority
serverlet.com. 2849 SOA ns1.serverlet.com. info.serverlet.com. 2026022188 10000 7200 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0