MaxClients actually tells the apache to allow this many concurrent clients.
Normally this limit is at 150. You can change this limit by editing your httpd.conf file.
httpd.conf is normally located at /etc/httpd/conf/httpd.conf
ServerLimit directive to let the value of MaxClients above 256 work.
By deafult ServerLimit is 256 (and is usually not already there in httpd.conf). If it is in your httpd.conf increase it above 256 or if it is not there add it in your httpd.conf
Press CTRL + W to find maxclients
Change MaxClients from 150 to any value below 256.
By Default MaxClients Maximum Value is 256.
If you want to increase it more above 256 you can do that but for that you need to follow the steps below.
You need to change the
Now you can change your MaxClients uptop 500