systemd[1]: Can’t open PID file /var/run/pure-ftpd.pid (yet?) after start: Too many levels of symbolic links
systemd[1]: pure-ftpd.service start operation timed out. Terminating.
systemd[1]: Failed to start Pure-FTPd FTP server.
systemd[1]: Unit pure-ftpd.service entered failed state.
systemd[1]: pure-ftpd.service failed.

vi /usr/lib/systemd/system/pure-ftpd.service

[Service]
Type=forking
#PIDFile=/var/run/pure-ftpd.pid
PIDFile=/run/pure-ftpd.pid
ExecStart=/usr/sbin/pure-config.pl /etc/pure-ftpd/pure-ftpd.conf –daemonize

systemctl daemon-reload
systemctl start pure-ftpd