authns1.alticeusa.com has no MX records.
Question and response
Question
dig authns1.alticeusa.com. MX
Answer
The response has no answer records.
Authority
alticeusa.com. 900 SOA authns1.cv.net. domain-admin.alticeusa.com. 2017134921 3600 600 604800 900
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0