ptr.terago.net has no MX records.
Question and response
Question
dig ptr.terago.net. MX
Answer
The response has no answer records.
Authority
ptr.terago.net. 3600 SOA ns1.terago.ca. ipnoc.terago.ca. 2025121500 10800 3600 604800 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0