Hi, Welcome to the Community!
I’m guessing you haven’t heard of or used Widevine before?
If that is the case, I would start there, by turning it on here:
brave://settings/extensions
Widevine
Use Widevine digital rights management (DRM) component to view protected streaming video and other content in the browser
First give that a shot, and BE SURE to RELAUNCH BRAVE, as it says to do & see if that fixes it. If it doesn’t come back and we’ll keep trying.
Also, Widevine is a Gxxgle component, obviously since Gxxgle runs Chrxme it’s on by default but due to Brave wanting to be as Anti-Gxxgle as possible (which I love and why I’m typing that the way that I am) they give the option to opt-in or out of using it. 
For future reference, I’d recommend you adhere to the community guidelines…
Guidelines - Before posting, please:
- Search the forum to see if anyone else has already posted or resolved the same issue you’re having. (For best results go to https://community.brave.app/search by clicking the magnifying glass and the filters icon to the right within ths search field and use the filters for better accuracy).
- Ensure that you’re posting in the appropriate category — please use the appropriate category when posting to ensure that whoever assist you has a clear idea of what product or platform you are using.
- Fill out the template that appears in your editor when posting as it contains all the boiler-plate information surrounding your issue. It will help the Support team members and other Community members to efficiently assess and resolve your issue. NOTE: “Uncategorized” posts do not have a template, so please ensure you’re posting to the right category as mentioned above.
- Tag your post appropriately – use tags to help track and organize threads on this forum.
- Observe and adhere to our code of conduct