C++ Read Access Error while Printing List

I'm trying to create a basic linkedList then print next node of head node but i get a runtime error.

class LinkedListNode
{
public:
    LinkedListNode* next = NULL;
    string data;
    LinkedListNode(string data)
    {
        this->data = data;
    }
};

class LinkedList
{
public:
    int count = 0;
    LinkedListNode *head;
    void add(LinkedListNode obj)
    {
        LinkedListNode* browser = head;
        while (browser->next != NULL)
            browser = browser->next;
        browser->next = &obj;
        count++;
    }
};

int main()
{
    LinkedList list;
    list.head = new LinkedListNode("headnode");
    LinkedListNode a1("a1");
    LinkedListNode a2("a2");
    list.add(a1);
    list.add(a2);
    cout << list.head->next->data << "\n"; // <- HERE ERROR OCCURS 0xC0000005: 0xCCCCCCCC 
    cout << list.count;
}

Am i doing something wrong i cant figure out the reason of 0xC0000005: 0xCCCCCCCC