Fail2ban no work

Stealth

sudo fail2ban-client status:
2021-07-08 15:00:58,308 fail2ban [2040]: ERROR [[Errno 111] Connection refused] Unable to contact server. Is it running?

Delete, reinstall, working. Restart server, again: ERROR [[Errno 111] Connection refused] Unable to contact server. Is it running?

Is this bug?

When try start from command:
2021-07-08 15:08:28,977 fail2ban [2217]: ERROR Fail2ban seems to be in unexpected state (not running but the socket exists)

Stealth

Okay this help a temporarily:
https://serverfault.com/questions/391433/fail2ban-dont-want-to-start-the-server

sudo service fail2ban start

Yet is 25% (1 core) at full load, 24/7 nonstop:
https://prnt.sc/19hp0jt

Without Fail2ban 0-3% CPU usage.

aaPanel_Captain

Is there any site protection added? If there is aaddition, check whether there i a scanning attack. If there is a scanning attack, it will take up some CPU performance

and alsoServer protection log