Route not defined?

Hello.

I'm trying to make a search on the same page in my admin dashboard.

here's what I did in my controller:

  public function search(){

        $q = Input::get ( 'q' );
        if($q != ""){
            $case = Case::where ( 'donation_title', 'LIKE', '%' . $q . '%' )->orWhere ( 'donation_story', 'LIKE', '%' . $q . '%' )->paginate (5)->setPath ( '' );
            $pagination = $case->appends ( array (
                'q' => Input::get ( 'q' )
            ) );
            if (count ( $case ) > 0)
                return view ( 'admin.cases.index' )->withDetails ( $case )->withQuery ( $q );
        }
        return view ( 'admin.cases.index' )->withMessage ( 'No Details found. Try to search again !' );


    }

my route :

 Route::post('/search/case','CasesController@search')->name('admin.search_cases');

my from :

    <div class="container">
        <form action="{{route('admin.search_cases')}}" method="POST" role="search">
            {{ csrf_field() }}
            <div class="input-group">
                <input type="text" class="form-control" name="q"
                       placeholder="Search cases"> <span class="input-group-btn">
                    <button type="submit" class="btn btn-default">
                        <span class="la la-search"></span>
                    </button>
                </span>
            </div>
        </form>
    </div>

Im getting :

Route [admin.search_case] not defined. 

I checked the route list PHP php artisan route:list and I cant see it

PS: I tried to clear the cache and config nothing changed

any idea whats going on here?