Hello,
Thank you for posting in Q&A forum.
Yes, it's a common practice if you get such error message for a internal network. As these are external DNS resolution request but you didn't configure any DNS forwarder to forward these request, it will fail to resolve the domain name internally.
I would suggest you list the most often quried external URL and put it into a new created DNS zone on DNS server.
It will help resolvet the external domain name and also keep your network environment far away from the Internet.
To help other customers who may be facing the same issue, please don't forget to vote if the reply is helpful.
Hope this answer can help you well.
Best regards,
Jill Zhou