I’ve setup a server with LAMP stack on ubuntu 14.04 but Apache keep crashing randomly.

I’ve followed this tutorial:
https://www.digitalocean.com/community/tutorials/how-to-optimize-apache-web-server-performance

The Apache error log shows:

AH00484: server reached MaxRequestWorkers setting, consider raising the MaxRequestWorkers setting

and multiple:

AH00045: child process 12845 still did not exit, sending a SIGTERM

before the crash. I’ve many websites in production on this server and I really want to fix it as soon as I can (that will save my nights) :-)

Is anyone has the same issue or can help me?

Thanks a lot