after looking in the settings and trying everything I could think of, I couldn't get the ListenBrainz Player to actually play music without manually having to play the YouTube video with every new track. that said, the player seems to think it is playing... the progress bar progresses, and it'll log the listen, even though the embedded YouTube video isn't playing

I'm on the current version of Firefox, and the relevant settings seem to be under Privacy & Security > Permissions > Autoplay

I set ListenBrainz.org as an exception to the rule, as well as YouTube.com, I even set it to allow audio and video, seemingly to no effect

it's possible this does not effect Spotify, I can't currently test this, as I don't have Spotify Premium...