ucgn-1b85e400.sec.ppp.nifty.com has no MX records.
Question and response
Question
dig ucgn-1b85e400.sec.ppp.nifty.com. MX
Answer
The response has no answer records.
Authority
nifty.com. 900 SOA odns0.nifty.ad.jp. hostmaster.nifty.ad.jp. 2026030300 3600 900 3600000 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0