Please try to play some songs from the official Spotify app first (iLightShow isn't a music player, it syncs the lights to the Spotify Connect service).
Try to sign out and sign in again with your Spotify account from iLightShow
Please check that you're using the exact same login method and credentials from both Spotify and iLightShow. Spotify doesn't check if the Facebook account you use is actually linked to an actual Spotify account while logging in.
Make sure the "Private Session" is disabled from the Spotify settings. If this option is enabled, iLightShow cannot detect the playback.
If you're 100% sure you're logged into the right account but still doesn't work, then you can try to delete and reinstall both Spotify and iLightShow. For some reasons, the Spotify Connect service sometimes needs it.
Please note that some smart speakers don't support the Spotify Connect service very well. For instance, the Sonos speakers work better while selecting the Sonos zone from the list of streaming services (instead of Spotify from the list).
Please make sure you've granted the access to Apple Music and that you're playing the music from the official Apple Music for iOS.
If you want to stream the music to a HomePod, please use Airplay. Apple doesn't offer any development kit for the homepod, using Airplay is the only way to get enough information about the current song/playback.
If you want to stream the music to some Sonos speakers, you can either use the same method as described for the HomePod above, or use the official Sonos App. If you use the official Sonos App, please select the Sonos speaker from the list of Streaming services.
Please note that iLightShow only supports Spotify & Apple Music, no matter if you use the services directly or with Sonos speakers.
Please make sure you stream the music to the Speakers directly (either via Spotify Connect, AirPlay, or using the Sonos App). If you stream the music to a TV, which is then connected to a Sonos system via HDMI, iLightShow won't be able to fetch the playback details.
If you don't see the Sonos speakers in the list of available services, please make sure your phone is connected to a WiFi network.
If it still doesn't find it or doesn't detect the music playback, please try to unplug-plug the AC power cord from the Sonos speakers, their system sometimes stops responding.
iLightShow isn't compatible with other services at the moment.