spf.otenet.gr has no MX records.
Question and response
Question
dig spf.otenet.gr. MX
Answer
The response has no answer records.
Authority
spf.otenet.gr. 1800 SOA ns1.otenet.gr. hostmaster.ns1.otenet.gr. 2021030901 10800 3600 1814400 1800
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0