Keep getting errors using Eloquent Relationships Laravel

I keep getting trying to get property of non-object anything am using laravel Eloquent Relationships. i Know that the eloquent relationship code is correct but i keep getting error.

This is my Video Controller

   class Video extends Model
  {
protected $fillable = [
    'vid',
    'v_img',
    'v_bg_img',
    'v_title',
    'v_description',
    'category_id',
    'previous_view',
    'previous_like',
    'today_view',
    'today_like',
    'daily_view',
    'daily_like',
    'weekly_view',
    'weekly_like',
    'promoted',
    'linked',
    'vid_entry_date'
];


public function videoRank()
{
    return $this->belongsTo('\App\VideoRank', 'category_id');
}
   }

This is my Video Rank Controller

  class VideoRank extends Model
      {

protected $fillable = [
    'rankName',
    'minRank',
    'maxRank'
];

public function video(){
    return $this->hasMany('\App\Video','category_id');
}

}

This is my blade view

               @foreach($videos as $video)
                    <tr class="odd gradeX">

                        <td></td>


                    </tr>
                @endforeach

I keep getting error 'Trying to get property of non-object '

via Chebli Mohamed