3.app.pap.linode-us-tx.qualityunit.com has no MX records.
Question and response
Question
dig 3.app.pap.linode-us-tx.qualityunit.com. MX
Answer
The response has no answer records.
Authority
linode-us-tx.qualityunit.com. 300 SOA pdns3.qualityunit.com. www.qualityunit.com. 2026021214 43000 7200 1209601 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0