rt.ntfo.org has no CNAME records.
Question and response
Question
dig rt.ntfo.org. NS
Answer
The response has no answer records.
Authority
ntfo.org. 3416 SOA ns1.everett.org. postmaster.ntfo.org. 2026022402 3600 14400 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0