To fix music error -42800 you’ll need to go to your settings>music>In the “Audio” section Turn off “Dolby Atmos”>click on “Audio Quality”>turn off “Lossless Audio” then go back to music settings>In the “Downloads” section turn off “Download in Dolby Atmos”
After all steps are complete you’ll need to go to your music and all the songs you have downloaded you’ll need to delete the “download” and download again.
This happens usually after a repair to device and the new part for some reason is causing a hardware/coding issue that makes the new sound settings from Apple not compatible.
I’ve tried all the steps on the internet and this is the only way it’s guaranteed to work.
Turning off the new Apple sound settings and for future downloads will have your songs playing with the old settings which we all had before with no problems and really not much difference between sounds.
Hope this helps.