Who to connect in filezilla with provided ftp credentials ?

Hello,
From my client I received ftp account and sample listing, that credentials are valid:

ubuntu@ip-CLIENT_IP:~$ ftp CLIENT.REMOTE.SERVER
Connected to CLIENT.REMOTE.SERVER.
220 ProFTPD Server (ProFTPD) [CLIENT.SERVER.IP]
Name (CLIENT.REMOTE.SERVER:ubuntu): SERVERUSER
331 Password […]

See original post by invalid@example.com (mstdmstd)