DNS Lookup Health Check

What domain does the DNS lookup actually try to reach out to the servers and request? Does it try to go to peplink.com for example?

I’m in a situation where i’m behind a customers firewall and the DNS Lookup check is failing. I’d like to be able to confirm that its not a firewall issue.

Did a little test and I see its sending traffic out to the DNS server on port 443 when it first connects, so I think that answers my question sort of.