Firefox Version After 63.03 - No Sound over RDP From Singsnap.com and also no live sound from Arlo Camera Portal Revert back to 63 Fixed Issue.
While I was on v67, I tried the config change with the sandbox being changed from 5 to 2. That did not enable sound on either Singsnap or my Arlo portal. If I view recordings of the security camera, sound does come through. If I go live, it does not. I tried using MS Edge and it worked through there. I am also able to listen to and watch videos on Youtube, with the v67, over RDP. It just doesn't want to play sounds from certain things, whereas, Edge will.
I ensured that my audio was using "remote audio," while I was testing, and as I said, other sounds worked.
Reverting to v63 immediately fixed the problem for both Singsnap.com and my Arlo live video from my cameras.