Issue Bind9 issue - All Queries to ns2.xxx.com for xxx.in/DNSKEY timed out or failed

[kartik]

Server operating system version

RHEL 8

Plesk version and microupdate number

18.0.56

I have parked two domain on RHEL8 system and bind9 service is running in chroot environment. I have enabled DNSSEC for both Domain1 & Domain2. When I am analyzing DNSSEC problems for xxx.in domain from DNSSEC Debugger site. I am getting "All Queries to ns2.xxx.com for xxx.in/DNSKEY timed out or failed" and "All Queries to ns1.xxx.com for xxx.in/DNSKEY timed out or failed" error (Screenshot attached) but no error is showing while analyzing abc.com domain (screenshot attached). I also observed some random query is coming to server (Screenshot attached) but no idea how to mitigate this issue. Someone please help me to mitigate the issue.

Details:
Domain1=xxx.in
Domain2=abc.com
Nameserver1=ns1.xxxxx.com (Authoritative Name Server for xxx.in & abc.com)
Nameserver2=ns2.xxxxx.com (Authoritative Name Server for xxx.in & abc.com)