cannot find main module

[Rwandevops]

Hi!
I tried to create a buffalo project following this tutorial: https://gobuffalo.io/fr/docs/getting-started/new-project/. I set the GO111module to "on".
The command $ buffalo new coke ends with "go: cannot find main module; see 'go help modules'".

What's wrong? I did not find this issue on the web.