spf1.manta.telconet.net has no MX records.
Question and response
Question
dig spf1.manta.telconet.net. MX
Answer
The response has no answer records.
Authority
manta.telconet.net. 900 SOA srv1.telconet.net. abuse.telconet.net. 235 10800 3600 2419200 900
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0