You can find lfd log (login failure daemon) on /var/log/lfd.log and also we can check logs in /var/log/messages and other logs you can find in your CSF logfile /etc/csf/csf.logfiles

thank you for your answer

If you are facing this problem then try to check by this way go to logs in /var/log/messages and in other logs you can find CSF logfile.

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