Phoenix1.Level3.net has no MX records.
Question and response
Question
dig Phoenix1.Level3.net. MX
Answer
The response has no answer records.
Authority
Phoenix1.Level3.net. 3600 SOA ns2.Level3.net. dns.level3.net. 2026030609 7200 600 2592000 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0