cloudron.blockbluemedia.com has no CNAME records.
Question and response
Question
dig cloudron.blockbluemedia.com. NS
Answer
The response has no answer records.
Authority
blockbluemedia.com. 1800 SOA carl.ns.cloudflare.com. dns.cloudflare.com. 2397569711 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0