I had the same problem and I think its related to ads. I realized that spotify locked after an ad played but the ad had disappeared. I had to log in on my computer and get songs to play again. There was a weird ad loop but once songs started to play on my account on the computer they also worked on the Roku
This made me think about whether I had paused an ad on my phone when I had listened earlier I hadn't but I played a few seconds from my phone and paused. Then I tried to play the playlist I wanted on the TV. It worked! Thank you so much for posting your experience.
Best answer! I just spent about an hour trying to figure out why I couldn't get Spotify to actually "play" on my Roku. Tried everything - reboot, uninstalling and reintalling, turning on and off, etc. Then I checked this site and saw your message. Sure enough, when I changed the setting at the bottom of my Spotify app on my COMPUTER, magically the sound came back on my TV. Thanks so much for your suggestion!
I'm using Roku Stick 3800X, software version 9.1.0
This problem has been occuring for me nonstop yesterday and today (I think I'm on try #7 in the past 24 hours). It happens every time I pause the app for a few minutes and then try to restart, and once the audio just dropped out on its own.
The 'Fix' (go to computer, play something, log back onto Roku) worked the first few times, but the has become less and less reliable. (It's taking more and more random clicking around the computer app before anything will play on roku.)
My additional annoyance is I'm trying to listen to podcasts, so it's not as simple as just finding a song or a spot in a playlist. If I try to play my episode on the computer, it's inevitably saved to a point 20 minutes before I stopped listening, and when I get it to work on the roku I've then got to forward to where I left off.
I dont' know if the fact that I'm listening to a 2 hr+ episode is causing a problem - I know other users have related the issue to skipped/frozen ads.
I've updated the software, removed/reloaded the app, etc.