ds0.opaltelecom.net has no MX records.
Question and response
Question
dig ds0.opaltelecom.net. MX
Answer
The response has no answer records.
Authority
opaltelecom.net. 300 SOA ds0.opaltelecom.net. noc.opaltelecom.net. 2025040900 600 7200 2592000 300
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0