Why std::vector resize fails?

I am trying to resize vector defined over a defined custom class

class Product{
private:
    Product *next;
    int pid;

public:
    Product(int _pid): pid(_pid){}
};

int main(){
    vector<Product> v;
    v.resize(1, Product(1));
    v[1] = Product(1);
    v.resize(2, Product(2));
}

My code is failing when i try to resize it second time, I have looked over other answers but I couldn't really get the idea behind it.

I have a requirement where I need to resize the vector.

Could someone please explain it and any workaround for it?