The login details for the Upload FTP are:

Hostname/server -> upload.4netplayers.de
Username/login -> IP of the game server WITHOUT the port
Password -> The FTP password you set

The login details for the log files FTP are:

Hostname/server -> logs.4netplayers.de
Username/login -> IP of the game server WITHOUT the port
Password -> The LOG FTP password you set

If you no longer know the password, you can check it in "Configure -> IP and FTP settings".