Switching from pureftp to proftp through WHM says it completed, but you’re still running pureftpd? Try to do it on the commandline and see this error?
Problems were detected with cPanel-provided files which are RPM controlled.
If you did not make these changes intentionally, you can correct them by running:
> /usr/local/cpanel/scripts/check_cpanel_rpms --fix
The following RPMs are missing from your system:
Removing 0 broken rpms:
rpm: no packages given for erase
Hooks system enabled
Checking for and running RPM::Versions 'pre' hooks for any RPMs about to be installed
All required 'pre' hooks have been run
No RPMS need to be uninstalled
Installing new rpms: pure-ftpd-1.0.36-8.cp1136.x86_64.rpm
Preparing packages for installation...
Waiting for ftpserver to restart.........finished.
pure-ftpd (/usr/sbin/pure-ftpd -O clf:/var/log/xferlog --daemonize -A -c50 -B -C20 -D -E -fftp -H -I15 -lextauth:/var/run/ftpd.sock -L10000:8 -m4 -s -S21 -U133:022 -u100 -i -Oxferlog:/usr/local/apache/domlogs/ftpxferlog -o -k99 -Z -Y0 -JHIGH:MEDIUM:+TLSv1:!SSLv2:+SSLv3) running as root with PID 10940 (process table check method)
pure-authd (/usr/sbin/pure-authd -s /var/run/ftpd.sock -r /usr/local/cpanel/bin/pureauth) running as root with PID 10944 (pidfile check method)
ftpserver: [ != 220]
ftpserver has failed, please contact the sysadmin.
Prelinking shared libraries and binaries: /usr/sbin/prelink -av -mR
Check pureftpd.conf for this line:
[~]# grep CallUploadScript /etc/pure-ftpd.conf
If you find that line uncommented, it’s likely you have CXS installed. One of the requirements of CXS is
Pure-ftpd, compiled with --with-uploadscript for ftp upload scanning
…so you’ll either need to uninstall CXS or find another workaround.