CSF integrated UI stops working after few minutes

I have a Centos web server without any control panel like cPanel

I've installed CSF/LFD and I've configured it to enable the integrated UI

It was working fine using port 6666, but after few minutes the UI not working at all

And I have to reboot the whole server to let the UI works again, but after minutes the UI doesn't work again

while the UI is working, I found this line in the results of the "csf -p" command

6666/tcp     4/-  -     (2442/root)          lfd UI                                  /usr/bin/perl

and while it's not working, I didn't find that line