Configure php memory limit
The memory could be configured in several places.
Set memory_limit to 512M:
sudo vi /etc/php5/cgi/php.ini sudo vi /etc/php5/cli/php.ini sudo vi /etc/php5/apache2/php.ini sudo vi /etc/php5/fpm/php.ini
Restart service:
sudo service service php5-fpm restart sudo service service nginx restart sudo service apache2 restart