使用php将推文添加到MySQL数据库

Trying to add tweets from my timeline to my database, unable to do so, I'm getting the error, "Tweet creation cannot be done at this moment." Any suggestions? I have a table named tweets with the following columns: name, screen_name, text, created_at, id_str, followers_count

<?php
    define('DBHOST','localhost');
    define('DBUSERNAME','');
    define('DBPASSWORD','');
    define('DBNAME','');
    define('TWEETTABLE','tweets');

    require_once('TwitterAPIExchange.php');

    /** Set access tokens here - see: https://dev.twitter.com/apps/ **/
    $settings = array(
    'oauth_access_token' => "...",
    'oauth_access_token_secret' => "...",
    'consumer_key' => "...",
    'consumer_secret' => "..."
    );
    $url = "https://api.twitter.com/1.1/statuses/user_timeline.json";

    $requestMethod = "GET";

    $getfield = '?q=%23photogridly';
    $twitter = new TwitterAPIExchange($settings);
    $string = json_decode($twitter->setGetfield($getfield)
    ->buildOauth($url, $requestMethod)
    ->performRequest(),$assoc = TRUE);
    if($string["errors"][0]["message"] != "") {echo "<h3>Sorry, there was a             problem.</h3><p>Twitter returned the following error message:</p><p>     <em>".$string[errors][0]["message"]."</em></p>";exit();}
    foreach($string as $items)
    {
        echo "Tweeted by: ". $items['user']['name']."<br />";       
        echo "Screen name: ". $items['user']['screen_name']."<br />";
        echo "Tweet: ". $items['text']."<br />";                
        echo "Time and Date of Tweet: ".$items['created_at']."<br />";
        echo "Tweet ID: ".$items['id_str']."<br />";
        echo "Followers: ". $items['user']['followers_count']."<br /><hr />";
        echo insertTweets($items['user']['name'],$items['user']['screen_name'],$items['text'],$items['created_at'],$items['id_str'],$items['user']['followers_count']);
    }

    function insertTweets($name,$screen_name,$text,$created_at,$id_str,$followers_count){
        $mysqli = new mysqli(DBHOST, DBUSERNAME, DBPASSWORD, DBNAME);
        if ($mysqli->connect_errno) {
            return 'Failed to connect to Database: (' . $mysqli->connect_errno . ') ' . $mysqli->connect_error; 
        }
        $prepareStmt='INSERT INTO '.DBNAME.'.'.TWEETTABLE.' (name, screen_name, text, created_at, id_str, followers_count) VALUES (?,?,?,?,?,?);';
        if ($insert_stmt = $mysqli->prepare($prepareStmt)){
            $insert_stmt->bind_param('ssssid', $name,$screen_name,$text,$created_at,$id_str,$followers_count);
            if (!$insert_stmt->execute()) {
                $insert_stmt->close();
                return 'Tweet Creation cannot be done at this moment.';
            }elseif($insert_stmt->affected_rows>0){
                $insert_stmt->close();
                return 'Tweet Added.';
            }else{
                $insert_stmt->close();
                return 'No Tweet were Added.';
            }
        }else{
            return 'Prepare failed: (' . $mysqli->errno . ') ' . $mysqli->error;
        }
    }              ?>

Here's the screenshot of the output