Arkadaşlar basit bir içerik ekleme sistemi yazdım içerikleri ekliyorum sorunsuz çalışıyor fakat 3 yada 4. içeriği eklerken aşağıdaki hatayı veriyor nerede yanlışlık yapıyorum ?

Fatal error: Uncaught Error: Call to a member function execute() on bool in C:xampphtdocsprojectadminsettingsislem.php:218 Stack trace: #0 {main} thrown in C:xampphtdocsprojectadminsettingsislem.php on line 218

https://i.hizliresim.com/7Wcpf8.png

if(isset($_POST['content_add'])){ 
//$uploads_dir="../../assets/uploads/content";
$mysql_add_content=$conn->prepare("insert into content(c_title,c_title_en,c_description,c_description_en,c_date)values(

    '".$_POST["c_title"]."',
    '".$_POST["c_title_en"]."',
    '".$_POST["c_description"]."',
    '".$_POST["c_description_en"]."',
    '".$_POST["c_date"]."')");

    if($mysql_add_content->execute()){
         $last_id = $conn->insert_id;
        

            Header("Location:../slider-ekle.php?durum=ok");
            $r1=rand(20000,32000);
            $r2=rand(20000,32000);
          
            $uploaded_images = array();
            foreach($_FILES['upload_images']['name'] as $key=>$val){
            $upload_dir = "../../assets/uploads/content/";
            $upload_file = $upload_dir.$r1.$_FILES['upload_images']['name'][$key];
            $filename = $r1.$_FILES['upload_images']['name'][$key];
            if(@move_uploaded_file($_FILES['upload_images']['tmp_name'][$key],$upload_file)){
            $uploaded_images[] = $upload_file;
            $insert_sql = "INSERT INTO photos(c_id, url, upload_time)
            VALUES('$last_id', '".$filename."', '".time()."')";
            
            $run=$conn->prepare($insert_sql);

            if($run->execute()){
            Header("Location:../icerik.php?durum=ok");

            }else
            Header("Location:../icerik.php?durum=error");

            }
            }
            

        }
      

}