Authentication Errors with SFTP Client

[DHolmes01]

Hi there, I have managed to set up SFTPGo on a google cloud compute engine instance (with gcs) and I can connect to it using the webUI and it works quite well, but as soon as I try to connect from an SFTP client (FileZilla for example) or via an sftp ... command I get errors like this

I have tried both username and password authentication, as well as key authentication, but both give the same result, with an occasional error like this

I would like to be able to connect using a username and password as I don't want to have to set up keys for each new device. Are there any configuration issues within SFTPGo that could be the issue?