ptr31.lnh.edu.pk has no CNAME records.
Question and response
Question
dig ptr31.lnh.edu.pk. NS
Answer
The response has no answer records.
Authority
lnh.edu.pk. 21 SOA julio.ns.cloudflare.com. dns.cloudflare.com. 2397929450 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0