Recently Added Tracks Not Showing Up:

• Check your Offline Listening Settings page.
• If you have enabled "Only save via Wi-Fi" and are trying to save over a 3G/4G/5G or LTE connection, either connect to Wi-Fi or disable the "Only save via Wi-Fi" setting.

Tracks and Playlists Disappeared:

• Offline content is temporarily stored in your mobile device’s SoundCloud app.
• If you uninstall the app or sign out, you will lose all offline content. Before doing so, consider if you’re prepared to re-save your Library for offline listening after reinstalling or signing back in.

Rights holder issue:

• SoundCloud ensures that the rights holder can control how and in what countries they want their tracks to be available to listeners. 
• If a track is not available for offline listening in a playlist or your Library with your SoundCloud Go subscription, this is because the rights holder of the track has chosen to disable the ability to listen to the track offline. 

General offline listening Issues:

• Ensure you are connected to a stable Wi-Fi network if you’ve set your app to only save content via Wi-Fi.
• Restart the app and try refreshing your Library or playlist by pulling down the screen.