mail.gabia.net has no MX records.
Question and response
Question
dig mail.gabia.net. MX
Answer
The response has no answer records.
Authority
gabia.net. 300 SOA ns.gabia.co.kr. hosting.gabia.com. 2021072609 1800 600 1209600 300
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0