mta02-rdb.dblc.io has no MX records.
Question and response
Question
dig mta02-rdb.dblc.io. MX
Answer
The response has no answer records.
Authority
dblc.io. 600 SOA nsa01.corp.dblc.io. admin.dabcnet.net. 2026022601 600 600 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0