dnvrco-postmx01.email.rr.com has no MX records.
Question and response
Question
dig dnvrco-postmx01.email.rr.com. MX
Answer
The response has no answer records.
Authority
email.rr.com. 3600 SOA dns1.rr.com. hostmaster.charter.com. 2025060000 43200 3600 2419200 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0