Hello everyone !
I'm currently using google cloud to manage my VM instances and i have a Windows Server 2016 installed, i managed to configure my FTP server (using IIS) to access it from my computer but it can't seems to connect and i don't know the reason why. WinSCP keeps popping up this error : "Could not retrieve directory listing - Error listing directory '/'. "
Solved !
Sorry ! I got it work by opening some ports i specified in the IIS ( using VPC network firewall rules GUI in the google cloud console ) .