After updating PHP last week it appears that it actually broke wordpress backends. This is actually a quick fix. The full error is below.
PHP Fatal error: Call to undefined function wp_dashboard_setup() in /var/www/vhosts/yourdomain.com/httpdocs/wp-admin/index.php on line 15, referer: http://yourdomain.com
So to fix this all we have to do is go to line 15 in the wp-admin/index.php file and edit the following line:
require_once(ABSPATH . ‘wp-admin/includes/dashboard.php’);
edit it with so that it looks like the following:
You should now be able to log into your Woredpress site now. Also if you are missing your widgets you can exit the same line in the wp-admin/widgets.php file.