Known Issue: If you are using LearnDash and Grassblade with Wax LRS and your users get an error stating "LRS Invalid" when they try to complete courses, it means your site scheme (http://yoursite.com) where the course content is hosted differs from the LRS site scheme (https://yoursite.waxlrs.com). The browser refuses to communicate and send data to Wax LRS because of a cross domain request from http (non SSL) to https (SSL secured). This is a known issue in all versions of Internet Explorer.
This is happening because Wax LRS does not support http as this causes a huge security hole, where credentials are transmitted.
Solution: Offer your courses/lessons over https (get an SSL certificate). You can do this by getting an SSL certificate for your LearnDash site and make sure that all iFrames are secured over SSL as well. This is beneficial because it offers your clients improved security.
Please contact us or open a support ticket if you have any additional questions.