I already tried it, ie I removed the old vsftpd.pem
I created a new one with the command:
sudo openssl req -x509 -nodes -days 3650 -newkey rsa:2048 -keyout /etc/ssl/private/vsftpd.pem -out /etc/ssl/private/vsftpd.pem
I changed the entries:
CN = kris … on IP adress / hostname … and when logging in to FileZilla for the first time, there were no errors and red entries when verifying the certificate.
But it did not do anything when connecting FTP (vsftpd) to CE … once I managed to connect and check the login and password and approve them … but it was not possible to list directories with audio video files again … .upssss.
You can endlessly test this way without success … something is wrong with FTP server VSFTPD / CE / TLS
my configuration that works fine on FileZilla (/etc/vsftpd.conf)
anonymous_enable=NO
listen_port=XXXX
local_enable=YES
chroot_local_user=YES
virtual_use_local_privs=YES
dual_log_enable=YES
listen=YES
tcp_wrappers=YES
rsa_cert_file=/etc/ssl/private/vsftpd.pem
rsa_private_key_file=/etc/ssl/private/vsftpd.pem
ssl_enable=YES
user_config_dir=/etc/vsftpd_user_conf
guest_enable=NO
pam_service_name=ftp
nopriv_user=XXXXX (login ftp)
allow_writeable_chroot=YES
allow_anon_ssl=YES
force_local_data_ssl=YES
force_local_logins_ssl=YES
xferlog_enable=YES
write_enable=YES
download_enable=YES
write_enable=YES
anon_other_write_enable=YES
utf8_filesystem=YES
use_localtime=YES
ssl_ciphers=HIGH
ascii_upload_enable=YES
ascii_download_enable=YES
pasv_enable=YES
pasv_min_port=
pasv_max_port=
EUREKA !!! 
… thanks @vpeter for your patience!
I managed … but it helped to generate a new certificate (without errors, the so-called red entries when logging in to FileZilla) I also copied the file: /etc/ssl/private/vsftpd.pem from the vsftpd server to CE path: /storage/.config (but whether did it matter?)
However, it was very important to enter the path to the FTP server resources! I always typed: /media/filmy because that was how it was set for a given virtual user. And you only had to enter:
/|auth=TLS
and the path showed automatically! (from ftp server settings)
maybe it will be useful to someone