1.40.200.in-addr.arpa has no MX records.
Question and response
Question
dig 1.40.200.in-addr.arpa. MX
Answer
The response has no answer records.
Authority
1.40.200.in-addr.arpa. 3600 SOA ns1.anteldata.com.uy. dns-admin.antel.net.uy. 2006111001 10800 1800 604800 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0