Maximum file limit reach error is occur while we are starting the Apache server at that time you can fix the issue by using root login details.

root@gunjan[~]#pico /etc/sysctl.conf
Add following line as

fs.file-max = 22992

Save and exit from the file.

You need to run following command from shell to active changes.

root@gunjan[~]#sysctl -p
It will increase the maximum number of open files for your Server.