I need help on this subject as well. It seems like an IP has been blocked, but I can’t fix it.
I followed instructions here and deleted the rows from the oc_bruteforce_attempts table (there were 8 from said IP), but still cannot even load the nextcloud webpage from the IP in question. Is there anywhere else it might be blocked?
I had to find the correct jail so I could unlist the IP, then I added the IP to the fail2ban’s whitelist.
So I ran “fail2ban-client status” to get a list of jails and figured out which one it was.
Then to unlist it I ran “fail2ban-client set JAILNAME unbanip IPADDRESS”
Added the IP address to /etc/fail2ban/jail.local in the “ignore ip=” section.
I had someone else set this up for me and I’m figuring it out as I go, didn’t know fail2ban was installed.