$server = "dbxxxxxxxx.db.1and1.com";
$dbname = "dbxxxxx";
$dbusername = "dboxxxxxx";
$dbpassword = "xxxxxxxx";

header('Content-Type: application/json');
try {
    $pdo = new PDO("mysql:host={$server};dbname=test;charset=utf8", $dbusername, $dbpassword);
} catch (PDOException $e) {
    error_log($e->getMessage());
    die(json_encode(["query" => 1])); // fails
}
if (isset($_GET['wewn'], $_GET['piec'], $_GET['zew'], $_GET['humid'], $_GET['jasno'])) {
    $stmt = $pdo->prepare("INSERT INTO sensor (value,value2,value3,value4,value5) VALUES (:wewn,:piec,:zew,:humid,:jasno);");
    $stmt->execute([
        ':wewn' => $_GET['wewn'],
        ':piec' => $_GET['piec'],
        ':zew'  => $_GET['zew'],
        ':humid' => $_GET['humid'],
        ':jasno' => $_GET['jasno']
    ]);
    echo json_encode(["query" => 0]); // ok
}

print_r($_GET);

?>