spf-3p-1.o2.com has no MX records.
Question and response
Question
dig spf-3p-1.o2.com. MX
Answer
The response has no answer records.
Authority
o2.com. 900 SOA n1.02.net. hostmaster.02.net. 2026022401 10800 3600 604800 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0