Apache Error Invalid argument: couldn’t grab the accept mutex

Apache HTTP Server is a free and open-source web server that delivers web content through the internet. It is commonly referred to as Apache and after development, it quickly became the most popular HTTP client on the web. Some high-profile companies using Apache include Cisco, IBM, Salesforce, General Electric, Adobe, VMware etc.

And this topic will explain how to resolve  the issue, when you are getting following error on apache error log:

(22)Invalid argument: couldn’t grab the accept mutex
(22)Invalid argument: couldn’t grab the accept mutex
(22)Invalid argument: couldn’t grab the accept mutex

Solution:

Typically, these type of errors occur on systems low on memory or file handlers.

Of note, one suggested resolution for the error message would be to try adding the following line to /usr/local/apache/conf/httpd.conf 
AcceptMutex fcntl

Run Apache distiller on the server using the following commands:

/usr/local/cpanel/bin/apache_conf_distiller –update –main
/scripts/rebuildhttpdconf
/etc/init.d/httpd graceful