I’m using the latest (as at August 2020) ver of Volumio on a Pi4 using local web interface on Windoze.
I have what seems to be an old problem with Spotify in that it works fine EXCEPT I can’t see any of my playlists. I’ve read the stuff on the forum but it seems quite old and wondering if there’s any update on the issue. If the answer involves going into the Volumio installation on the Pi plse bear in mind that I’m a Linux klutz and not sure how to access it.
It’s more a case of a series of changes at Spotify over a time period giving a similar result 
Volumio v2.806 is working fine with Spotify on several devices here.
Some questions about your installation (it’s always good to provide as much info as possible please).
Did you enable the plugin after installation, and enter your Spotify premium username and password correctly?
Did you authorize the Volumio plugin to access your Spotify account (an external page from Spotify should appear in a separate tab)?
Did you try rebooting after installation?
Have you tried removing the plugin, and reinstalling it checking for errors during the installation process?
Many thanks for your really quick response.
YES to ALL your questions about my actions.
Actually I seem to have a result now. I’ve been accessing Volumio via my Windows desktop recently, due to being somewhat Coronavirus housebound. Just tried it from my Android tablet and it all works perfectly, so it seems to be something to do with the Windows access - ie the Android app is doing something that the browser based access isn’t? Other than Spotify, the Windows based access works really well and Spotify works apart from my playlists.