Allowed memory size of 262144 bytes exhausted

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

Thanks to: https://stackoverflow.com/questions/4096582/allowed-memory-size-of-x-bytes-exhausted/30118084#30118084