Ah, another day, another silent regression by @GooglePlayMusic --- this time, the (Linux version of the) "Music Manager" application, whose only purpose is to upload one's music to The Cloud, has stopped working, for no reason.
Sorry for the trouble – mind sharing the screenshot of the error message (if any)? Try checking the Chrome version of the music manager if it's working fine then re-install the desktop app. Also, make sure that you have a strong internet connection too. Keep us posted.
