smtpb14.lacoocan.nifty.com has no MX records.
Question and response
Question
dig smtpb14.lacoocan.nifty.com. MX
Answer
The response has no answer records.
Authority
nifty.com. 900 SOA odns0.nifty.ad.jp. hostmaster.nifty.ad.jp. 2026030400 3600 900 3600000 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0