From bab-tec.de wiki
SET UP SPOTIFY
If you want to listen music from your Spotify account via your AUDIO MODULE, you have to perform additional setup steps in the Logitech Media Server. Please proceed as follows:
1. Click on Settings of the Logitech Media Server web interface.
2. Now go to the tab "Plugins".
3. Now, enable the Spotty plugin (this can be found at the 3rd party plugins, which are only visible if the AUDIO MODULE has access to the internet). After the plugin have been activated, it is necessary to restart the Media Server. This usually happens automatically. After the restart, you have to change again to the "Settings/Plugin" page, to adjust the Spotty Plugin settings.
4. Under the Spotty Plugin settings enter the Spotify username and password and confirm with "Apply"
5. Finally, the following page is displayed after entering the user data. In this view you can delete the Spotify account.