You could have an error while using Soundiiz to transfer a playlist to SoundCloud or simply create a playlist SoundCloud with Soundiiz.
Be aware that SoundCloud has a limit of 8000 playlists.
There's also a limit of 500 tracks per SoundCloud playlist. However, to solve this issue, Soundiiz will create multiple playlists SoundCloud if your source playlist has more than 500 tracks.
So you will have X SoundCloud playlists with "_partX" at the end of a transfer process to SoundCloud if you got a large playlist as source.