Slow / no response from FreePBX web GUI

I have alterned some settings in intruder detection page (to adjust the ban time). Afterward, I found the web gui no long response on the IE located in a remote PC connected via vpn.

I then try to login with pc on the same LAN using chrome, the login was successful but the GUI response is very slow.

The resources is okay with the memory usage a bit high (yellow in color). But the GUI start to be un-responsive.

I restart the machine with ssh ‘reboot’, and the problem presist.

Interestingly, before the settings, I wont receive any email for fail2ban service start and stop, but I now consistantly receiving email telling me that my service is stopped / started, etc. Including SIP / FTP / SSH / PBXGUI. And an IP being banned.

Top command shows nothing using CPU, your help is appreciated.
Thanks alot.

It starts to response after my second restart of asterisk service. But I still have no idea why it was unresponsive. Thanks.