Thought this might be helpful to others who use Mullvad Browser.

Got to the advanced preferences and set webextensions.storage.sync.enabled to true.

    • @[email protected]
      4•1 year ago

      I started searching myself and found that too, though I can’t even get videos to play on the browser for some reason, even though the instance I tried works through Libretube, which I’ve been using for a good while now by the way and SponsorBlock is great on it!
      I wonder if it’s a web client bug