$query = mysqli_query($con, "SELECT * FROM users WHERE Username = '".$testname. "' OR Email = '".$testemail. "'");
$registered = time();

    if(mysqli_num_rows($query) > 0){
        echo "Username or email is already in use.<br>";
    }else{
        $sql = "INSERT INTO users (Username, Password, Email, Firstname, Lastname, Lastlogin, Registered) VALUES ('$testname', '$testpass', '$testemail', '$testfirstname' , '$testlastname', '$lastlogin', '$registered')";
        if ($conn->query($sql) === TRUE) {
            if($sql->errno === 1062) {
                echo "Username or email is already in use.<br>";
            }else{
                echo "New account created successfully<br>";
            }
        }else{

    }
}