mail0010.institut-aob.com has no CNAME records.
Question and response
Question
dig mail0010.institut-aob.com. NS
Answer
The response has no answer records.
Authority
institut-aob.com. 10800 SOA ns5.infomaniak.ch. hostmaster.infomaniak.ch. 2026022202 10800 3600 605800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0