I've debian 9
when I try to click on fail2ban-->jail--> f2bmng failed: ERROR:__main__:Command '['/usr/bin/dpkg', '-S', '/etc/fail2ban/jail.conf', '/etc/fail2ban/jail.d/plesk.conf', '/etc/fail2ban/jail.local']' returned non-zero exit status 1.
Follow also this docs: Fail2ban cannot to enable jail...