จะส่งค่าขึ้น host หลายรอบแล้วยัง error อยู่เลยครับ

<?php
    
// Prepare variables for database connection
    
$dbusername = "id3500299_sg2017";  // enter database username, I used "arduino" in step 2.2
    
$dbpassword = "0882134797";  // enter database password, I used "arduinotest" in step 2.2
    
$server = "localhost"; 
// IMPORTANT: if you are using XAMPP enter "localhost", but if you have an online website enter its address, ie."www.yourwebsite.com"
    
$My_db = "id3500299_smartguardian";
    
// Connect to your database
    
$dbconnect = mysqli_connect($server, $dbusername, $dbpassword,$My_db);
    
$dbselect = mysql_select_db("id3500299_smartguardian",$dbconnect);
    
// Prepare the SQL statement
    
$sql = "INSERT INTO Events (Message) VALUES ('".$_GET["c"]."')";    
    
// Execute SQL statement
    
mysqli_query($sql,$dbconnect);

?>