I installed the latest version hestiacp and failed to access FTP via port 21.
<<< 200 Switching to ASCII mode. >>> PASV <<< 500 OOPS: invalid pasv_address >>> CWD / Error EElFTPSUnacceptedReplyError: Unaccepted server reply code 500 to command PASV
Did you check whether range of TCP ports 12000-12100 are open in Hestia AND in the firewall used by your hosting provider (if it provides one)?
TCP
12000-12100
If the range of ports is open in both, Hestia and your provider and you can’t connect, add this directive pasv_addr_resolve=YES to /etc/vsftpd.conf file and once done, restart the service systemctl restart vsftpd and try again.
pasv_addr_resolve=YES
/etc/vsftpd.conf
systemctl restart vsftpd