autodiscover.outlook.com has no MX records.
Question and response
Question
dig atod-g2.tm-4.office.com. MX
Answer
atod-g2.tm-4.office.com. 60 CNAME autod.ms-acdc-autod.office.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0