mail.schlitt.net has no CNAME records.
Question and response
Question
dig mail.schlitt.net. NS
Answer
The response has no answer records.
Authority
schlitt.net. 10800 SOA dns.schlitt.net. wayne.schlitt.net. 2019071604 86400 14400 2419200 432000
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0