Unable to serve a Creator App

Hello there,
I just made a Creator App which I exported with:

$ionic start [Appname] creator:[App-ID]

Then I wanted to run it with

$ionic serve

But I got the following Error Message:

What is wrong here?

Thanks for helping.

I am on Bash on Ubuntu on Windows. The problem was that my windows build was too old. Logging in to Windows Insider and downloading the latest build solved the Problem.