You can access your hosting account with the secure FTP version SFTP (Secure File Transfer Protocol).
In your FTP client, change the default port (21) to port 5544. It is important that you select the server name login-XX.hoststar.ch (replace XX with the server number of your hosting account) and not your domain so that the correct SSL certificate will be used.
You also have the option to use FTPS (FTP Secure) with the default port (21).
For security reasons, Hoststar does not support access via SSH.