I updated to Android 8.0.0 and all was fine, my offline music was all still showing as downloaded, and had the green arrow next to it, but when I selected one to play it would play only nothing. The song then greyed out on the list of songs.
I have reinstalled several times, cleared all cache from the device, rebooted several times, cleared all my offline devices on the website (still trying to figure out how to make PC work offline again) and NOW... When I log in and try to make a playlist offline, even my total offline playlists that are on the SD card, it says "DOWNLOAD ERROR Downloading has stopped because there's no space left on the device." And then the Downloading says "waiting to download..." and doesn't do anything.
Internal Storage: 17.52GB used out of 32.00GB.
External Storage: 24.70 used out of 128GB. [Encrypted]