Hello,
Wanted to add to this thread. Same issue with the GUI indicating Fail2Ban not running, same error codes when attempting to start the service. Same Apache error - ‘filter.d/apache-api’ under /etc/fail2ban ERROR Unable to read the filter ERROR Errors in jail ‘apache-api’. Skipping…
Solution that worked for me on 4 FreePBX 15 was ashcortech in the last update.
Manually running
/var/www/html/admin/modules/sysadmin/hooks/fail2ban-apache-config