spf.belbone.be has no CNAME records.
Question and response
Question
dig spf.belbone.be. NS
Answer
The response has no answer records.
Authority
belbone.be. 88 SOA ns.belbone.be. hostmaster.belbone.be. 2011103649 10800 3600 2419200 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0