spf0.voipgrid.nl has no MX records.
Question and response
Question
dig spf0.voipgrid.nl. MX
Answer
The response has no answer records.
Authority
voipgrid.nl. 1800 SOA kyrie.ns.cloudflare.com. dns.cloudflare.com. 2397320820 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0