INTO INSERT avec OVH

$db_host = "localhost"; 
$db_username = "nom d'utilisateur"; 
$db_password = "mot de passe"; 
$db_name = "nom de la base de données"; 
$db_table = "nom de table"; 

$conx = mysqli_connect($db_host, $db_username, $db_password, $db_name) ; 
if (mysqli_connect_errno()) 
{ 
echo "Echec de la connexion: " . msqli_connect_error(); 
} 
else { 
echo "Connexion ok <br /> <br />"; 
} 
$sql = "INSERT INTO $db_name ('ID', 'prenom', 'nom', 'email') VALUES (NULL, 'marie', 'tartenpion', 'mt@aol.com')"; 
if (mysqli_query($conx, $sql)) { 
echo "Nouveau enregistrement créé avec succès"; 
} else { 
echo "Erreur : " . $sql . "<br>" . mysqli_error($conx); 
} 
// en retour d'OVH: Access denied for user $db_username@'%' to database $db_table 
$result = $conx->query('SELECT*FROM $db_name'); 
while(($donnees = $result->fetch_assoc())) 
{printf ($donnees['prenom']);} 

mysqli_close($conx); 

<?php
  $db_host = "localhost";
  $db_username = "nom d'utilisateur"; 
  $db_password = "mot de passe";
  $db_name = "nom de la base de données";
  
  $conx = mysqli_connect($db_host, $db_username, $db_password) ;
					if (mysqli_connect_errno())
						{
						echo "Echec de la connexion: " . msqli_connect_error();
						}
						else {
							echo "Connexion ok <br /> <br />";
						} 
  $sql  = "INSERT INTO $db_name (`ID`, `prenom`, `nom`, `email`) VALUES (NULL, 'xxxx', 'xxxxxx', 'xxxxxxx@xxx.xx');";					
      if (mysqli_query($conx, $sql)) {
         echo "Nouvel enregistrement ok  <br />";
         } else {
         echo "Erreur : " . $sql . "<br>" . mysqli_error($conx);
         }
  $result = $conx->query("SELECT*FROM $db_name");
  while(($donnees = $result->fetch_assoc()))
  		 {
		 echo "<br />";	 
         printf ($donnees['prenom']);
		 echo "<br />";
		 printf ($donnees['nom']);
		 }
		 
  mysqli_close($conx);
?>