LARAVEL: Error is parameterize() must be of the type array, null given

I am trying to add multiple column and when submitting the data then it's showing error like:

Argument 1 passed to Illuminate\Database\Grammar::parameterize() must be of the type array, null given, called in C:\xampp\htdocs\CERCAA\vendor\laravel\framewo

Here is controller:

1. public function store(Request $request) {

       $data = new past_events();
       $data->title = $request->title;
       $data->slug = $request->slug;
       $data->event_date = $request->event_date;
       $data->event_video_link = $request->event_video_link;
       $data->event_place_name = $request->event_place_name;
       $data->category_id = $request->category_id;
   
   
          $data->save();
          $id = $data->id; // foreign_key
          foreach ($request->Featured as $key=>$file){
           $speaker=new past_event_speaker();
           $speaker->past_event_id = $id;
           $speaker->Featured = $request->Featured[$key];
           $speaker->speaker_name = $request->speaker_name[$key];
           $speaker->speaker_position = $request->speaker_position[$key];
           $speaker->save();
       }
   
       foreach ($request->Featured1 as $key=>$file){
           $session = new past_event_session();
           $session->past_event_id = $id;
           $session->Featured1 = $request->Featured1[$key];
           $session->session_time = $request->session_time[$key];
           $session->event_session_name = $request- 
           >event_session_name[$key];
           $session->session_person_name = $request- 
           >session_person_name[$key];
           $session->session_person_topic = $request- 
           >session_person_topic[$key];
           $session->File =$request->File[$key];
           $session->save();
       }
   }
   

via Chebli Mohamed