To force Softaculous to re-check the licence you will need to run the cron, for cPanel servers this is as simple as logging into your server as the root user (SSH) and running the following command.
/usr/local/cpanel/3rdparty/bin/php /usr/local/cpanel/whostmgr/docroot/cgi/softaculous/cron.php
You should them be able to use Softaculous from WHM/cPanel.