b1.uberns.com has no MX records.
Question and response
Question
dig b1.uberns.com. MX
Answer
The response has no answer records.
Authority
uberns.com. 300 SOA a1.uberns.com. itmanager.uberns.com. 2021082001 14400 7200 1209600 300
Additional
. 0 OPT ; payload 1280, xrcode 0, version 0, flags 0