I created this question earlier but was told that it is a DNS issue as apposed to an issue with HSTS. Regardless, here is what I need help troubleshooting:
Issue:
A single site (one that I own), is showing server DNS address could not be found. DNS_PROBE_FINISHED_NXDOMAIN when I try to connect to it via chrome, firefox, or safari. I can however connect to it via Tor Browser. I can also verify that the address resolves correctly using mxtoolbox. I also am not able to connect via two other computers and two other phones. I also am not able to connect via a different WIFI connection or personal hotspot via my phone. Curl and Host via the command line are also not able to get a response.
What I've tried: As I said above, I've tried different internet connections and computers. I've also tried flushing my DNS cache and pointing to another DNS server.
Having said that, I am not sure how else to trouble shoot this. The only change I made to the web app was to add HSTS headers, hence why I created the earlier posing. Please let me know what other information I can provide. Otherwise, here are some details about the site itself:
Other information about my stack:
EDIT:
Possibly related: https://serverfault.com/questions/606880/how-can-i-troubleshoot-a-route-53-hosted-zone
So from our discussion regarding the NS server records always make sure that the local NS records matches the Parent NS records.
In your case there there were 2 extra NS records associated with your domain that was the reason why your domains and sub domains were acting unhealthy. once you deleted those records the domains and sub domains were back to normal.