Can’t Activate Licence yet again

This plugin works great when you can activate it, I use this on many sites, but I am now looking for an alternative that will allow me to run my courses in fullscreen mode, why? Because I have a key client site – and I have a valid licence but I cannot activate the licence on this one important site, so I get a link to the elearningfreak website on my course page and since this problem has occurred I cannot load new content, real shame because I love the plugin but it really isn’t working for me anymore.