Works for me. see screenshot Have you tried in safe mode?

Firefox safe mode: Click the menu button menu , click Help and select Restart with Add-ons Disabled…. Firefox will start up with the Firefox Safe Mode dialog.

Can you see what 3rd party cookies you may be blocking? see screenshot Just as a test, try another account to see if you have the same issue.

doesn't play in safe mode either, though it's not just a near blank page in safe mode firefox isn't showing any cookies for pandora time for the song is showing 0:00/0:00 like it's unable to fetch the song

issue seems to be resolved now