_spf.dotplex.com has no CNAME records.
Question and response
Question
dig _spf.dotplex.com. NS
Answer
The response has no answer records.
Authority
dotplex.com. 3521 SOA ns.dotplex.net. support.dotplex.com. 2026022302 86400 10800 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0