mx1c.odoo.com has no CNAME records.
Question and response
Question
dig mx1c.odoo.com. NS
Answer
The response has no answer records.
Authority
odoo.com. 253 SOA ns3.odoo.com. admin.odoo.com. 2021050400 10800 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0