I’ve had a similar issue with a different app before, it was caused by the Play Store (which also lead to automatic updates not working for a while). I fixed it by Force-Stopping the Play Store and relaunching it again.
Disclaimer: I’m using a custom ROM where the Google stuff is sandboxed (GrapheneOS), maybe the bug doesn’t occur on Stock Android.
It was possible to download lossless FLAC files (they got them straight from Deezer) though, so higher quality than anything downloaded from Youtube etc.