Can't reach Azure App Service from within my private LAN on a windows machine

Question

This morning I noticed that none of the web apps I am running in Azure is reachable anymore.
I first thought its an issue with Azure itself, but when I try to connect with a mobile hotspot (through my phone) everything works as expected.
The problem seems only to exist in my own LAN at home but only Azure is affected.

When I try to navigate to a website, I get the following message:

I also cannot nslookup it:

I do not have any problem with surfing the internet. All other sites work fine... but I don't even know where to start on solving this problem.
Does anybody know a tool to diagnose this? What could be wrong here...?

I did not have any issues with accessing the services yesterday.

Answer 1

In recent years, DNS has become the most vulnerable part of the internet, as many other components are strengthened significantly.

Like you discovered, for some unknown reasons the DNS your machine connects to failed to sync the proper Azure related records. That's not an uncommon issue if you read about how badly DNS infrastructure around the globe was maintained.

Usual solutions are,

• Switch to other DNS service than your default ISP provided ones, Google/Cloudflare public DNS servers are popular, and there are many other good options.
• Hack your hosts file (but that's too complicated).