webhost000 cannot insert data to database [duplicate]

I’m using webhoost000 to insert certain data but every time I try it returns the error message. I tried making a select statement and it works, I also try to use my query to the phpmyadmid and it also work i don’t understand why my code is not working
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$dbServername = "localhost";
$dbUsername = "id1911627_users";
$dbPassword = "MC{aJpz1_174]MTU";
$dbName = "id1911627_usersdata";

$conn = mysqli_connect($dbServername, $dbUsername, $dbPassword, $dbName);

if(!$conn){
    die("connection failed: ".mysqli_connect_error());
}

$db = "id1911627_usersdata";
$dbs = mysqli_select_db($conn, $db);

if(!$dbs){
    die("connection failed: ".mysqli_connect_error());
}

$un = $_GET['u'];
$pw = $_GET['p'];
$fn = $_GET['f'];
$age = $_GET['a'];
$gdr = $_GET['g'];

$sql = "INSERT INTO usersdata (username, password, fullname, age, gender, height, weight, bloodpreasure, sugarlvl) VALUES ('$un', '$pw', '$fn', '$age', '$gdr', '0', '0', '0', '0')";
$query = mysqli_query($conn, $sql);

if($query){
    echo "added";
}
else{
    echo "not ".$sql;
}