dns1.bigpond.com.kh has no MX records.
Question and response
Question
dig dns1.bigpond.com.kh. MX
Answer
The response has no answer records.
Authority
bigpond.com.kh. 86400 SOA dns1.online.com.kh. hostmaster.online.com.kh. 2022030701 14400 3600 691200 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0