How to manage example.com website from admin.example.com

Yes, it should be possible. (Did you post this question on Stack Overflow too? I have a suggestion there.)

But what's happening to cause a 505? That response means HTTP VERSION NOT SUPPORTED so I'd take a close look at any special headers you're setting.

No i've not posted something on stack overflow! Every issue related to codeigniter is suddenly unknown for them! Let's not talk about it!! 

I think that it's something related to the config of the image upload. Here's the part of the "Posts" controller where i set the config for the image upload:

Code:

$post_id = random_string('numeric', 7);
$dir_exist = false;
if( !is_dir('../../htdocs/assets/img/posts' . $post_id) ){
 mkdir('../../petvres/assets/img/posts' . $post_id, 0777, true);
$dir_exist = true;
}
if (!empty($_FILES['mainImg']['name'])) {
$config = array(
 'upload_path' => '../../htdocs/assets/img/posts/' . $post_id,
 'encrypt_name' => TRUE,
 'allowed_types' => 'gif|jpg|jpeg|png',
 'max_size' => '1310720',
 'max_width' => '2048',
 'max_height' => '2048'
);
$img_data = array();
$this->load->library('upload', $config);

...
(the rest of the controller code)

I think there's something wrong with the upload_path.

---

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}