@VannGuce thank you for your response!
Your message reminded me of configuring a global docker network’s DNS, but I couldn’t make it work as the docker for Windows container’s configuration is a bit tricky.
However, as a workaround, I was able to change my runner configuration to start all containers providing the “8.8.8.8” DNS and it worked!
Anyway, the behavior when the newly created “Windows server for containers” VM cannot reach any external resource, as the DNS is broken, doesn’t seem like something correct
Thank you a lot!