Here are some recommendations that will most likely resolve this issue. 

1. If you using a VPN or Remote Desktop program, please turn them off and access the course outside of these systems. The reason these can cause havoc is that organizational IT departments often save bandwidth by not allowing video traffic through them. 

2. Try using a different browser. Especially if the you are using Internet Explorer 11. Additionally, your version of Safari or Chrome is may out of date. 

3. Clear cookies and cache. To do this, log out of the eLearning site completely. Don't be on the site at all, with any browser tab. Then clear your browser history, specifically the cookies and cache. Once that is done, log back into the eLearning site and try again.

Here is a link that explains how to clear cookies and cache in most browsers after you have closed down any eLearning sites. https://www.whatismybrowser.com/guides/how-to-clear-cookies-browsing-history-and-cache/auto

This is different than restarting your computer or closing and re-opening your browser.