please replace downloadExcel function with the following line of codes.

JobseekerController.php

    //for download excel
    public function downloadExcel($type)
    {   
        ini_set('max_execution_time', 3000);
        set_time_limit ( 3000 );
        $user = new Jobseeker;
        $data = $user->query();
        try{
            $filedate = str_replace(' ', '_', Carbon::now());
            return Excel::create('UserList'.$filedate, function($excel) use($data){
 
            $data->chunk(10000, function ($users) use($excel) {
            $collection = $this->transformCollection($users);

            $excel->sheet('OrgSubUserList', function($sheet) use($collection){
                $sheet->fromModel($collection, null, 'A1', true);
            });
            });
            
        })->export('xlsx');
        }
        catch(Exception $e)
        {
            return false;
        }
       
    }