Laravel - DELETE method is not support for a delete route

I'm a complete beginner at laravel and am currently making a simple admin panel. I have a grid that shows users (name, email, etc...) and the problem I have is probably stupid but I can't figure it out. I created a controller method for deleting a user:

public function destroy($id)
    {
        $user = User::find($id);
        $user->delete();

        return redirect('/admin')->with('success', 'User has been deleted');
    }

And defined route as this:

Route::post('/admin/delete/{id}', 'AdminController@destroy')    
    ->middleware('is_admin')    
    ->name('admin.destroy');

and to delete a user in grid, I used form in my view and even setup headers:

<td>
<form href="" method="post">
   @method('DELETE')
   @csrf
   <input class="btn btn-danger" type="submit" value="Delete" />
</form>

And everytime I press button for deleting a user, I get this:

The DELETE method is not supported for this route. Supported methods: GET, HEAD.

I just can't figure out what I'm doing wrong. I tried changing route type to post but I get the same error.

via Chebli Mohamed