sr04.imsbiz.com has no MX records.
Question and response
Question
dig sr04.imsbiz.com. MX
Answer
The response has no answer records.
Authority
imsbiz.com. 600 SOA ns5.imsbiz.com. dnsadmin.imsbiz.com. 2025091102 1800 900 604800 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0