Strange problem with file upload

Thank you @kirasiris, i made all of yur suggested modifications but no way. It's not working.
I want to ask one question: Is it possible that a file has mp3 extension but is not mp3 file?

This is what your code should look if you want it to send it to a database and into a folder.

PHP Code:

            // Upload mp3/Ogg File
            $config['upload_path'] = 'uploads/musiques/';
            $config['allowed_types'] = 'mp3|ogg';
            $config['encrypt_name'] = TRUE;
            $config['file_ext_tolower'] = 'TRUE';
            $config['remove_spaces'] = 'TRUE';
            $this->load->library('upload', $config);
            $this->upload->initialize($config);
                    
            
            $file_name = 'mymusic';
            
            if(!$this->upload->do_upload($file_name)){
                var_dump($this->upload->display_errors());
                $file_name = 'uploads/musiques/nofileselected.jpg';
            } else {
                $post_image =  $this->upload->data('file_name');
            }
            
            // If you want to send it to your database as well, you have to put it like this:
            $data = array(
                'slug'            => $slug,
                'title'            => $this->input->post('title'),
                'mymusic'    => $post_image,
            ); 


try and see if it works, and to respond your second question about uploading a file that looks like an mp3 file but its not, I will highly recommend you to convert any file into mp3 before uploading just to  make sure you dont mess with uploading class; or if you have any idea of what the real extension of the file is, then added it to the allowed_types parameter and see if it works.

I do Front-End development most of the time