_dmarc.sundials.org has no CNAME records.
Question and response
Question
dig _dmarc.sundials.org. NS
Answer
The response has no answer records.
Authority
sundials.org. 3570 SOA dove.chezaubert.net. jack.chezaubert.net. 555991 3600 1800 1814000 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0