UnityWebRequest hangs on isDone but not always

Hi guys Having a weird problem here hope someone might be able to help I have two buttons calling the same function, this function creates a web request to get a wav file from a specific path, this path is the same for both buttons , however one just gets the sample and plays it in an audio source and the other is suppose to get the sample load it to another audio source but not play it, the weird this is with the second button isDone never turns true and downloadProgress never goes above zero, therefore the function never reaches the next step where i test which button was pressed.

Really hope someone can help Regards!

 public string path;
 AudioSource aSource1;
 AudioSource aSource2;
 
 public IEnumerator SomeFunction ( bool isPreview ){
             AudioClip wavFile;
 
             UnityWebRequest www = UnityWebRequestMultimedia.GetAudioClip(path, AudioType.WAV);
             www.SendWebRequest();
 
             while (!www.isDone)
             {
                 yield return www.isDone;
             }
             // Button 2 never reaches this point
             if (www.isNetworkError)
             {
                 Debug.Log(www.error);
             }
             else
             {
                 wavFile = ((DownloadHandlerAudioClip)www.downloadHandler).audioClip;
 
                 if ( buttonNumber == 0)
                 {
                     aSource1.clip = wavFile;
                     aSource1.Play;
                 }
                 else
                 {
                      aSource2.clip = wavFile;
                 }
             }
 }