apps.xlhost.com has no NS records.
NS records for this zone are defined at xlhost.com.
NS records for this zone are defined at xlhost.com.
Question and response
Question
dig apps.xlhost.com. NS
Answer
The response has no answer records.
Authority
xlhost.com. 86400 SOA dns4.ee.net. hostmaster.ee.net. 2017030854 28800 7200 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0