My playlists are gone
Make sure you have signed in to the app using the same account you used to create playlists. To do this, hold the cursor over your account portrait in the upper-right corner. The username for the current account will appear.
If you added playlists in the app and can't find them in the web version of the app, it might be because your library has not synced yet. Try logging out of your account and then logging in again.
If certain tracks in the playlist are grayed out and you can't listen to them, it means that the period of the license agreement between the individual who holds the rights to the track and Yandex.Music has expired.
If the playlists don't appear even if you are using the correct account and your devices have synced, write to customer support.