_dc-mx.869aacc03fbc.smtp48.com has no AAAA records.
Question and response
Question
dig _dc-mx.869aacc03fbc.smtp48.com. AAAA
Answer
_dc-mx.869aacc03fbc.smtp48.com. 300 CNAME mail18.smtp12.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0