Have for a while experience issues with one website based on WP going up and down and not being available.

Checked “WooCommerce logs in dashboard”

At lot of fatal errors at the exact timestamp as the site became unavailable. A quick search revealed that I’m hitting the php memory ceiling of default 64M.

Solution: Upp the php memory to 256M

Located the wp-config.php file and added

define( 'WP_MEMORY_LIMIT', '256M' );

Just before the line

That’s all, stop editing! Happy blogging.

Restarted Apache

/etc/init.d/apache2 restart

Entered su password and done!