_spf-c.telia.net has no MX records.
Question and response
Question
dig _spf-c.telia.net. MX
Answer
The response has no answer records.
Authority
telia.net. 1200 SOA dns1.telia.com. backbone.telia.net. 2026021907 10800 3600 604800 1200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0