WWW not working on my PHPs

Hello. I am new to this, and I have followed the wiki tutorial "Server side highscores" in order to create a leaderboard on my server. Everything seems fine until I try to send/get the data within Unity, neither of them working properly. When I try to send data, null values are sent instead; and when I try to get it, I receive a string with content similar to a HTML script (with 'body' etc., nothing related to what I should receive). Doing these manually work without a problem. Here are the scripts:

test_insert.php ) or die('Could not connect: ' . mysql_error()); mysql_select_db('') or die('Could not select database');

     $id = mysql_real_escape_string($_GET['id'], $database);
     $msgid = mysql_real_escape_string($_GET['msgid'], $database); 
 
  
     echo $id . "\t" . $msgid;
     $query = "INSERT INTO test (id, msgid) VALUES('$id', '$msgid');";
     $result = mysql_query($query) or die('Query failed: ' . mysql_error());
 ?>

test_display.php ') or die('Could not connect: ' . mysql_error()); mysql_select_db('') or die('Could not select database');

     $query = "SELECT * FROM `test`";
     $result = mysql_query($query) or die('Query failed: ' . mysql_error());
  
     $num_results = mysql_num_rows($result);  
     for($i = 0; $i < $num_results; $i++)
     {
          $row = mysql_fetch_array($result);
          echo $row['id'] . ' ' . $row['msgid'] . '/';
     }
 ?>

Unity C#: using System.Collections; using System.Collections.Generic; using UnityEngine;

 public class phpstufftesting : MonoBehaviour {
     public string postinfolink = "http://***/test_insert.php?";
     public string getinfolink = "http://***/test_display.php";
 
     IEnumerator PostInfo(int id, string msgid){
         string post_id = postinfolink + "id=" + id + "&msgid=" + WWW.EscapeURL (msgid);
         Debug.Log (post_id);
         WWW hs_post = new WWW (post_id);
         yield return hs_post;
         if (hs_post.error != null)
             Debug.Log (hs_post.error);
     }
 
     IEnumerator GetInfo(){
         WWW hs_get = new WWW (getinfolink);
         yield return hs_get;
         if (hs_get.error != null)
             Debug.Log ("Error: " + hs_get.error);
         string info = hs_get.text;
         string[] each = info.Split ('/');
         for (int i = 0; i < each.Length; i++)
             Debug.Log (each [i]);
     }
 
     void Start () {
         StartCoroutine (PostInfo (5, "hello"));
     }
     
     // Update is called once per frame
     void Update () {
         
     }
 }
 

crossdomain.xml

 <?xml version="1.0"?>
 <!DOCTYPE cross-domain-policy SYSTEM
 "http://www.adobe.com/xml/dtds/cross-domain-policy.dtd">
 <cross-domain-policy>
     <site-control permitted-cross-domain-policies="master-only"/>
     <allow-access-from domain="*"/>
     <allow-http-request-headers-from domain="*" headers="*"/>
 </cross-domain-policy>

Retrieving data from other websites (tested for images from Google) works. Also, since I am only experimenting, I am using a free hosting service, but I don't believe this could be the problem behind this.