mail11.serenisys.com has no NS records.
NS records for this zone are defined at serenisys.com.
NS records for this zone are defined at serenisys.com.
Question and response
Question
dig mail11.serenisys.com. NS
Answer
The response has no answer records.
Authority
serenisys.com. 2560 SOA ns1.galaxie.cloud. hostmaster.serenisys.com. 2025101500 14400 3600 1209600 2560
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0