Unable to connect to google cloud platform instance via SFTP with Filezilla

Question

Does anyone know the proper way to connect Filezilla SFTP to WordPress Instance on Google's Compute Engine?

I generated the SSH keys and input it into Filezilla but it connects and then kicks me out.

I have tried following all the documentation provided by Google Cloud Platform:

• Connecting to Linux Instances
• Generating a new SSH key-pair

Any help will be much appreciated.

Thank you.