Why local WWW audio stream not working on iOS?

this works for android but on an iphone S5 the audio file is not been played. thanks in advance!

url = "file://" + Application.persistentDataPath + "/audio-"+ index +".mp3";
wwwTemp= new WWW (url);
yield wwwTemp;

You need to use like this
“file://” + Application.dataPath + “/Raw/” + “FOLDER/YOUR_FILE.MP3”;

Where “/Raw/AssetBundles/” will be your StreamingAssets folder inside the Assets

Android and iOS doesn’t work in the same way when using the StreamingFolder