1. Go to about:config in your address bar.

2. Search for webgl.force-enabled and make sure this preference is set to true. If it is currently set to false, click the toggle icon on the far right to change the value to true.

3. Search for webgl.disabled and make sure this preference is set to false. If it is currently set to true, click the toggle icon on the far right to change the value to false.

4. Restart Firefox to apply your new settings.

https://support.biodigital.com/hc/en-us/articles/218322977-How-to-turn-on-WebGL-in-my-browser