si.12.arsysinternet.com has no MX records.
Question and response
Question
dig si.12.arsysinternet.com. MX
Answer
The response has no answer records.
Authority
arsysinternet.com. 86400 SOA dns1.servidoresdns.net. hostmaster.servidoresdns.net. 2001102343 21600 3600 2419200 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0