This account has reached it's limit of concurrent processes - fixing a Wordpress issue

"This Account Has Reached it's limit of concurrent processes".

We got stuck with this problem on our hosting account that hosts about a dozen Wordpress sites.
After checking our server logs, wp-cron.php appeared to be the culprit.

Wp-cron.php helps by doing some automated things like posting scheduled content, checking comments for spam, and emailing comment notifications.  The problem is that wp-cron.php loads on every single page view, so this could be running hundreds, thousands, or millions of time each day, depending on your website traffic.

To stop wp-cron.php from running on every page visit, add this near the top of wp-config.php

define('DISABLE_WP_CRON', true);

To run wp-cro.php at your own chosen interval, create a cron job that runs every hour with the following line.  If your site only receives one or two comments per day, the cron job could be run every 12 or 24 hours.

wget -O /dev/null http://www.example.com/wp-cron.php?doing_wp_cron

via: wp-cron.php – How To Stop It From Running Frequently