sender28000.picsrv.net has no MX records.
Question and response
Question
dig sender28000.picsrv.net. MX
Answer
The response has no answer records.
Authority
picsrv.net. 60 SOA dns1.proxi.nl. hostmaster.copernica.com. 1730734843 14400 1800 86400 60
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0