verify.bing.com has no MX records.
Question and response
Question
dig ax-0001.ax-msedge.net. MX
Answer
The response has no answer records.
Authority
ax-msedge.net. 60 SOA ns1.ax-msedge.net. msnhst.microsoft.com. 20240309 1800 900 2419200 60
Additional
. 0 OPT ; payload 1224, xrcode 0, version 0, flags 0