If you are running your servers with "LiteSpeed Web Server" 


There is 1 settings to be added in wp-config.php:define('ALTERNATE_WP_CRON', true);

That solved the issue I had with UPDRAFT and my other plugin "All-in-One WP Migration"...


It may required as well to update the .htaccess as follow:

RewriteBase /
RewriteRule .* - [E=noabort:1]