std::dynamic_pointer_cast<> によるダウンキャストがビルドエラーになる原因が知りたい。

提示コードですが以下のGame.cppですがなぜ以下のエラーが出るのでしょうか？エラーコードの意味も含めて対象法がわかりません。
スマートポインタを参考サイト通りダウンキャストしているのですが原因がわかりません。

知りたい事

エラーコードの意味と対象方法が知りたい。

参考サイト：https://chiku2gonzalez.hatenablog.com/entry/2014/10/23/230011

Error

shigurechan@shigurechan-System-Product-Name:~/Program/SDLGame/libTest$ make
g++ -c -MMD -MP src/Enemy.cpp -o obj/Enemy.o
g++ -c -MMD -MP src/Game.cpp -o obj/Game.o
g++ -c -MMD -MP src/Main.cpp -o obj/Main.o
g++ -c -MMD -MP src/Player.cpp -o obj/Player.o
In file included from /usr/include/c++/11/memory:77,
                 from src/../../lib/src/GameObject.hpp:6,
                 from src/../../lib/src/SDLGame.hpp:9,
                 from src/Player.hpp:6,
                 from src/Player.cpp:1:
/usr/include/c++/11/bits/shared_ptr.h: In instantiation of ‘std::shared_ptr<_Tp> std::dynamic_pointer_cast(const std::shared_ptr<_Tp>&) [with _Tp = SDL::BoxCollision; _Up = SDL::Component]’:
src/Player.cpp:31:46:   required from here
/usr/include/c++/11/bits/shared_ptr.h:603:23: error: cannot ‘dynamic_cast’ ‘(& __r)->std::shared_ptr<SDL::Component>::<anonymous>.std::__shared_ptr<SDL::Component, __gnu_cxx::_S_atomic>::get()’ (of type ‘using element_type = std::remove_extent<SDL::Component>::type*’ {aka ‘class SDL::Component*’}) to type ‘using element_type = using element_type = std::remove_extent<SDL::BoxCollision>::type*’ {aka ‘class SDL::BoxCollision*’} (source type is not polymorphic)
  603 |       if (auto* __p = dynamic_cast<typename _Sp::element_type*>(__r.get()))
      |                       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
make: *** [Makefile:25: obj/Player.o] エラー 1
shigurechan@shigurechan-System-Product-Name:~/Program/SDLGame/libTest$

Game.cpp

cpp
1
2void Player::Collision(std::shared_ptr<SDL::GameObject> obj)
3{
4	//std::type_info info(SDL::BoxCollision);
5	
6	addComponent(typeid(SDL::BoxCollision));
7	std::dynamic_pointer_cast<SDL::BoxCollision>(getComponent(typeid(SDL::BoxCollision)))->isEnable = true; //ここのコード
8}

GameObjec.hpp

cpp
1
2std::shared_ptr<SDL::Component> SDL::GameObject::getComponent(const std::type_info& info)
3{
4    if(std::string(info.name()) == std::string(typeid(SDL::BoxCollision).name()))
5    {
6        return std::dynamic_pointer_cast<Component>(boxCollision);
7    }
8    else if(std::string(info.name()) == std::string(typeid(SDL::CircleCollision).name()))
9    {
10        return std::dynamic_pointer_cast<Component>(circleCollision);
11    }
12    else if(std::string(info.name()) == std::string(typeid(SDL::LineCollision).name()))
13    {
14        return std::dynamic_pointer_cast<Component>(lineCollision);
15    }
16    else if(std::string(info.name()) == std::string(typeid(SDL::Sprite_Render).name()))
17    {
18        return std::dynamic_pointer_cast<Component>(spriteRender);
19    }
20    else
21    {
22        return nullptr;
23    }        
24
25}
26
27void SDL::GameObject::addComponent(const std::type_info& info)
28{
29    if(std::string(info.name()) == std::string(typeid(SDL::BoxCollision).name()))
30    {
31        boxCollision = std::make_shared<BoxCollision>();
32    }
33    else if(std::string(info.name()) == std::string(typeid(SDL::CircleCollision).name()))
34    {
35        circleCollision = std::make_shared<CircleCollision>();
36    }
37    else if(std::string(info.name()) == std::string(typeid(SDL::LineCollision).name()))
38    {
39        lineCollision = std::make_shared<LineCollision>();
40    }
41    else if(std::string(info.name()) == std::string(typeid(SDL::Sprite_Render).name()))
42    {
43        spriteRender = std::make_shared<SDL::Sprite_Render>();
44    }        
45}
46
47