_spf4.china-entercom.net has no MX records.
Question and response
Question
dig _spf4.china-entercom.net. MX
Answer
The response has no answer records.
Authority
china-entercom.net. 3600 SOA dns1.cibonet.com. mis.china-entercom.net. 2019042604 900 600 86400 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0