4G network versus wifi network post www php mysql data

Hello Guys,

I made a function for posting data by www to a PHP script, but it seems to fail when I switch from wifi to 4g mobile network provider. My function is as follows:

StartCoroutine(PostScores(Convert.ToInt64(FBProfile.ProfileId), FBProfile.FirstName, persistentDataScript.score, persistentDataScript.lastLevel));

 IEnumerator PostScores(Int64 facebookId, string name, int score, int levelId)

 {

     string oneSignalUserId = PlayerPrefs.GetString("OneSignalUserId");
     //string oneSignalUserId = "802ca4bc-74d7-11e5-b486-13d20ae9ed32";

     //This connects to a server side php script that will add the name and score to a MySQL DB.
     // Supply it with a string representing the players name and the players score.
     string hash = MyFunctions.Md5Sum(oneSignalUserId + facebookId + name + score + levelId + secretKey);

     string post_url = addScoreURL + "onesignaluserid=" + oneSignalUserId + "&facebookid=" + facebookId + "&name=" + WWW.EscapeURL(name) + "&score=" + score + "&levelId=" + levelId + "&hash=" + hash;
     Debug.Log(post_url);
     
     // Post the URL to the site and create a download object to get the result.
     WWW hs_post = new WWW(post_url);
     yield return hs_post; // Wait until the download is done
     
     if (hs_post.error != null)
     {
         Debug.Log("There was an error posting the high score: " + hs_post.error);

         errorPanel.SetActive(true);

     }
     else
     {

         uploadScorePanel.SetActive(false);

     }

 }

 public void OnErrorYesClick ()
 {

     Application.LoadLevel(Application.loadedLevelName);

 }

It gives my error panel again and again. Someone experienced this issue and know a way around?

Thanks, Maarten