thank you for the reply, I’m following instructions provided here:
" Now go to Plugins → Installed Plugins on Volumio and activate the plugin, putting in your Spotify Premium account credentials. On the third line, where it is asking for your Spotify refresh token, click the “i” icon to the right of the text field and you will see a line with the URL **54.86.144.136:8888 . Go to that URL in a separate browser window, authenticate with your Spotify Premium account credentials, and cut and paste the Refresh Token into the field on the Volumio Spotify credentials screen. Hit the Save button.|"