I have searched all over for a fix to this and haven't come across one. I just got a new iPhone after selling my other one, and first turned off iCloud music library to sync 33GB of music from my iMac. After that, I turned on the switch for iCloud Music Library but it refuses to stay on, with a message popping up saying that it's temporarily unavailable and I can turn it on later in settings. I'm not sure if this is an iOS11 bug or what, as I can see my library on other devices still. I have: Signed out of my iCloud account twice and then back in. Shut down the phone and hard reset the phone Reset and erased all settings I really don't want to restore the phone and start all over again but I'm not sure what else to do.