i5.bartheltubes.com has no CNAME records.
Question and response
Question
dig i5.bartheltubes.com. NS
Answer
The response has no answer records.
Authority
bartheltubes.com. 2943 SOA dns.iwelt-ag.net. domainmaster.iwelt-ag.net. 2024121701 43200 3600 2419200 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0