Hi! I faced this issue too when I was trying to set up Fail2Ban.
Here's how I fixed it:
(service fail2ban-service-type
(fail2ban-configuration
(extra-jails
(list
(fail2ban-jail-configuration
(name "sshd")
(enabled? #t)
(extra-content (list
(plain-file "filter"
"filter=sshd[_daemon='sshd-session']")))
(action (list
(fail2ban-jail-action-configuration
(name "nftables")))))))))
You could tweak this configuration, as I was using nftables.
