How to use Publii cms with Easy Engine v4?

I’m trying to create a static website using Publii cms, but I can not connect to the folder
‘/opt/easyengine/sites/’ via Publii cms.

Even giving 777 permission via ssh in the terminal, the folder does not accept upload and also does not accept upload via Filezilla.

So, how to proceed?

Note: I’m using Ubuntu 18.04 in the Google Cloud.