This happens when the DJ you are listening with is from a different region, and the song (or the version) they are playing is not available in your membership region.
As all music KKBOX provide have been legally authorized by record labels, the authorizations comes with an expiry date. Once the authorizations expires, the song/album will be temporarily removed from our library while we negotiate authorization renewal.
Sometimes music may be made available again under different information. We suggest doing a quick search before submitting your request through Customer Service →[Music and Other Recommendations] → [Can't find specific music].