Hi Claudio,
Looks like you’re hitting a connectivity issue, independent from SonarQube itself (the error comes from the underlying stacks, in this case Node.js).
No surprise here, older versions were based on different technologies.
All in all, similarly to this topic (or this one) you need to understand why the node process (or maybe the OS itself) on the VSTS agent fails to connect to the SonarQube URL you provide.