Here is a checklist:
- Shell access for the (non admin) account has to be set to rssh access.
- The SSH service needs to be reachable. Do you forward port 22 on your firewall to your SME server?
- SSH access is ok if you can logon to your server with (e.g.) PuTTY as user root (or as another user who has bash access).
- If necessary check the SSH settings in the server manager (Remote access). The settings need to be 'Allow public access' (unless you're doing SFTP on your local network only) and two times 'Yes'.
- In FileZilla you choose 'SFTP using SSH2' as Servertype and the portnumber is usually 22.
- Logontype is normal.
- Provide FileZilla the username (that has rssh access) and a password and you're done!