lightspeed.knvltn.sbcglobal.net has no MX records.
Question and response
Question
dig lightspeed.knvltn.sbcglobal.net. MX
Answer
The response has no answer records.
Authority
lightspeed.knvltn.sbcglobal.net. 300 SOA ns0.attdns.com. eiss-dns.att.com. 2019041201 3600 1800 2592000 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0