Frozen panel information and logs

I installed the ISPConfig3 panel on 06/08 and the logs on the monitor tab are frozen on 07/08.
The logs of fail2ban, cron, system, queue of emails, etc. They are all frozen with information from 07/08.
By the terminal, the tail -f /var/log/syslog command for example is displaying correctly.
SO: Debian 9.

What can it be?
Thank you

 

I discovered the error thanks to your response. Because of a "PHP Deprecated" error as per the line below, I saw a possible solution in git's ISP. But when I changed I did it wrong and so froze the panel logs. Now I've got it. It's OK.

PHP Deprecated: The each () function is deprecated. This message will be suppressed on further calls in /usr/local/ispconfig/server/lib/classes/cron.inc.php on line 267

Now reviewing did again and so far I no longer receive the warning messages about "PHP Deprecated".

Is there any problem I change directly in the file /usr/local/ispconfig/server/lib/classes/cron.inc.php? If I have an update to ISPConfig, would I lose these changes?

Now you are receiving only these warnings below:

Fri Aug 10 12:40:01 -03 2018 PHP Warning: Use of undefined constant openvz_tools - assumed 'openvz_tools' (this will throw an error in a future version of PHP) in / usr / local / ispconfig / server / lib / classes /cron.d/100-monitor_openvz.inc.php on line 72
Fri Aug 10 12:40:01 -03 2018 PHP Warning: Use of undefined constant openvz_tools - assumed 'openvz_tools' (this will throw an error in a future version of PHP) in / usr / local / ispconfig / server / lib / classes /cron.d/100-monitor_openvz.inc.php on line 101


Thank you very much

 

I wanted to try a solution for this case. I understand they are just warning messages .. it bothers me these warning messages ...
Thank you for your attention and help