sbs has no MX records.
Question and response
Question
dig sbs. MX
Answer
The response has no answer records.
Authority
sbs. 900 SOA ns0.centralnic.net. hostmaster.centralnic.net. 1771767043 900 1800 6048000 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0