https://arstechnica.com/gadgets/2017/12/amazon-music-ends-mp3-upload-support-will-end-music-storage-service-in-2019/

One feature of Amazon Music allows users to upload their own MP3 files from other sources, but that service is shutting down over the next year or so. According to a help page on Amazon's website, the company will end its Amazon Music Storage subscription service in January 2019. An official date hasn't been released, but once the storage service ends, users won't be able to play or download MP3s they previously uploaded.

Amazon already removed the ability to upload personal MP3s to Amazon Music through its PC and Mac apps earlier this week. The company's dedicated music importer software shuttered even earlier, back in 2015.