kube.bringe.net has no MX records.
Question and response
Question
dig kube.bringe.net. MX
Answer
The response has no answer records.
Authority
bringe.net. 300 SOA ns1.bringe.net. hostmaster.bringe.com. 2026021300 86400 7200 604800 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0