Alexa Suddenly Can’t Find My Apple Music Playlists

Since the weekend, Alexa is telling me that she can’t find playlists on Apple Music that she’s been playing almost every day for years. Additionally, any music she does play comes from Amazon Music, even though Apple is set as the default. I don’t think I’ve changed any settings and my Apple Music subscription is still live. Also, Sync Library is enabled.

What could possibly have gone wrong? Literally nothing changed, but overnight she just won’t play my music.