apache shutdown error , couldn’t release the accept mutex

to fix apache error

couldn’t release the accept mutex

in debian & ubuntu

do that

1. Create the following file: /etc/apache2/conf-available/mutex.conf
2. Add Mutex file:${APACHE_LOCK_DIR} default inside the newly created file
3. Enable new configuration file with a2enconf mutex
4. Restart Apache with systemctl restart apache2