Hi,

A few things to try:

1. Disable VPN or ad blocker; these frequently block YouTube/Vimeo embeds that Odoo eLearning uses.
2. Try a different browser; Chrome or Edge tend to have the best compatibility.
3. Check your network; if YouTube is restricted in your region/network, embedded videos won't play.
4. Clear cache and cookies, then reload the course page.

If none of those work, the video may be temporarily unavailable on Odoo's side; in that case report it via https://odoo.com/help with the specific course and slide name.