pretty sure you need to set this in jail.local, I’ve been using fail2ban for… 17yrs or so and have never heard of a jail.d folder… I could be behind the times on this, but then… mine works, so maybe not
for example, here is some of mine in jail.local that i have added
[nginx-deny]
enabled = true
port = http,https
filter = nginx-deny
logpath = /config/log/nginx/error.log
[bitwarden]
enabled = true
port = 80,443
filter = bitwarden
action = iptables-allports[name=bitwarden]
cloudflarev46
logpath = /extlogs/bitwarden/bitwarden.log
bantime = 14400
findtime = 14400
[authelia]
enabled = true
port = http,https,9091
filter = authelia
action = iptables-allports[name=authelia]
cloudflarev46
logpath = /extlogs/authelia.log
maxretry = 3
bantime = 1d
findtime = 1d