Why can't I use the "Replace" method in my synchronizations?
We use as much as possible official APIs (developers' access) to retrieve your music collection on a music service and then import it to another platform. These APIs are not always allowing developers to delete tracks in a playlist or reorder them. Due to this limit, this "Replace" method is not possible depending on your destination.
We are always trying to convince as many music services as possible to allow us such a delete option, but some still prefer not to offer this API access.
About Apple Music limitations
Unfortunately, Apple has removed "Delete" methods from its API, which means we can no longer delete tracks in a playlist or a playlist.
That's why you got an error 104 "Feature not available for this platform" if you are syncing with a "Replace" method or using any "Replace to" feature, for example.
It will also be impossible to update a playlist (like updating the title, for example) as the Apple Music API is not providing such an " Update " method.
Workaround when using the "Synchronization" feature for Apple Music
While it's impossible to sync correctly with an Apple Music playlist as a destination (also, because the Apple Music API doesn't playlist in your curator profile), it could be a great solution to use Apple Music as the source of your Syncs!
For that, it's pretty easy. Go to the Apple Music playlist and use the Share option, copy the link and get the URL. Once done, you can create a new Sync, and in the source, use the first option, "Playlist URL" and paste here the previous URL.
Now, Soundiiz will use this Apple Music playlist as the source for your synchronization to other music services and DSP!