Erro Path cannot be empty

Boa noite, professor

Ao tentar salvar a série inserindo uma imagem jpeg encontro o seguinte erro: Path cannot be empty.

Segue o código abaixo

SeriesController:

 public function store(SeriesFormRequest $request)
    {
        $coverPath = $request->file('cover')->store('series_cover','public');

        $request->coverPath = $coverPath;


        $serie = $this->repository->add($request);

        EventsSeriesCreated::dispatch(

            $serie->nome,
            $serie->id,
            $request->seasonsQty,
            $request->episodesPerSeason,
        );



        return to_route('series.index')
            ->with('mensagem.sucesso', "Série '{$serie->nome}' adicionada com sucesso");
    }

Model:

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;

class Series extends Model
{

    use HasFactory;

    protected $fillable = ['nome', 'cover'];

    public function seasons()
    {
        return $this->hasMany(Season::class, 'series_id');
    }

}

class EloquentSeriesRepository implements SeriesRepository:

class EloquentSeriesRepository implements SeriesRepository
{

    public function add(SeriesFormRequest $request): Series
    {
       return  $serie = DB::transaction(function() use ($request){

            $serie = Series::create([
               'nome'=> $request->nome,
               'cover'=> $request->coverPath, 

           ]);

            $seasons = [];

            for ($i=1; $i <= $request->seasonsQty; $i++) { 

               $seasons[] = [
                'series_id' => $serie->id,
                'number' => $i,
               ];
            }
               Season::insert($seasons);

               $episodes = [];
               foreach ($serie->seasons as $season) {
                for ($j=1; $j <= $request->episodesPerSeason; $j++) { 

                   $episodes[] = [
                  'season_id' => $season->id,     
                  'number' => $j,
                    ];

                    }
               }

               Episode::insert($episodes);

               return $serie;

        });
    }

Erro na linha $request->coverPath = $coverPath; Verifiquei o model, o create e o EloquentSeriesRepository. Está tudo conforme foi posto na aula. Como resolver este erro ?