Fatal Error: Cannot use object of type stdClass as array?

I'm quite new to PhP; My website suddenly stopped working tonight for no reason and once I have debugged my PDO script, it returns this error:

Cannot use object of type stdClass as array in /var/www/html/v1/framework/api/stats.php:5 Stack trace: #0 /var/www/html/v1/framework/radio_stats.php(5): include() #1 /var/www/html/v1/index.php(5): include('/var/www/html/v...') #2 {main}

I don't know if I'm doing something wrong, but everything seems to have broken.

$api = json_decode(file_get_contents('https://guardi.wearebounce.net/api/nowplaying'));
    if($api[0]->live->is_live == "true"){
        $return["presenter"] = $api[0]->live->streamer_name;
        $stmt = $pdo->query("SELECT * FROM `users` WHERE `username` = '".$return["presenter"]."'"); 
        $presenter = $stmt->fetch(PDO::FETCH_ASSOC);
        $presentera = $presenter["likes"];
    }else{
        $return["presenter"] = "AutoDJ";
        $presentera = -1;
        $presenter["avatar"] = "https://wearebounce.net/branding/LogoIconColour.png";
    }