spf.serverdata.net has no MX records.
Question and response
Question
dig spf.serverdata.net. MX
Answer
The response has no answer records.
Authority
spf.serverdata.net. 3601 SOA ns2.serverdata.net. hostmaster.serverdata.net. 2023042001 3600 1800 604800 3601
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0