Error in Filament's ImportAction Feature

fgetcsv(): Read of 8192 bytes failed with errno=21 Is a directory.

public static function table(Table $table): Table
    {
        return $table
        ->headerActions([
            ImportAction::make()
                ->importer(KiidMailPdfImporter::class)
        ])
     ...other code
    }

namespace App\Filament\Imports;

use App\Models\KiidMailPdf;
use Filament\Actions\Imports\ImportColumn;
use Filament\Actions\Imports\Importer;
use Filament\Actions\Imports\Models\Import;

class KiidMailPdfImporter extends Importer
{
    protected static ?string $model = KiidMailPdf::class;

    public static function getColumns(): array
    {
        return [
            ImportColumn::make('cstato')
                ->rules(['max:1']),
            ImportColumn::make('tuts')
                ->rules(['datetime']),
            ImportColumn::make('cisin')
                ->rules(['max:50']),

            ...other ImportColumn
        ];
    }

    ...other generated code