Cpanel ftp error – The data connection could not be established: ECONNREFUSED – Connection refused by server

# nano /etc/pure-ftpd.conf
# Port range for passive connections replies. - for firewalling.

PassivePortRange          50000 51000

Restart xinetd
Source: https://documentation.cpanel.net/display/CKB/How+to+Enable+FTP+Passive+Mode#HowtoEnableFTPPassiveMode-Passive