If you are on a Remote Desktop Connection (RDP) on Windows, audio playback will be disabled due to increased security restrictions. This is a known issue since Firefox version 56 that we are working hard to fix.
In the meantime, you can reduce the sandbox security level by following these steps:
- Type about:config in the address bar and press EnterReturn.
A warning page may appear. Click to go to the about:config page.
- Search for the security.sandbox.content.level preference.
- Click the Edit button next to the preference and set its value to 2.
- Click on the checkmark to save the change.
- Restart Firefox on the remote device.