Fail2ban with aaPanel is very bad. I using very long time, before no Fail2ban there in plugins...
On one server working, second no and canĀ“t start (deleted VPS later), on third have working (status cmd) but when open in aaPanel there is red pause symbol and text "Please start fail2ban service first" but working, tested it.
So very random bugs are there. Anytime when try start, say "successful start" and nothing, no symbol changed. When no have minimal Linux know-how, you never know why not start...
(Yet playing with Nginx on arm64 CPU, working, but after free firewall activation Nginx die, must uninstall to work again)