Windows 10 DNS issues

Solution 1:

This answer summarizes the research done by the poster and myself to analyze and fix the problem.

I describe here the sequence of actions that will (probably) fix the problem, followed by my theory why it works.

Step 1 : Stop the the DNS Client service

1. In the Start Menu of Windows, type services and click to run on Services
2. Find the service named DNS Client
3. Right-click the service and do Stop to stop it

Step 2 : Do network reset

1. In the Start Menu of Windows, click on Settings
2. Click on Network & Internet
3. Click on Status
4. Click Network reset
5. Click Yes

A detailed description can be found in this article. I believe that Network reset is probably equivalent to doing all the re-initialization commands listed above in the post.

Step 3 : Restart the DNS Client service

Repeat Step 1, but do Start instead to restart the service.
If the problem still occurs, try to reboot Windows.

My theory as to why it works

Apparently some bad setting related to the DNS Client service was introduced into Windows, which caused DNS to malfunction. Network reset is normally sufficient to bring the network to a known state, but in this case the bad setting could not be reset while the service was running. So the DNS Client service needed to be stopped for the Network reset to successfully reinitialize all the DNS settings.