Sum two Linked List

I got a node like this

  struct ListNode {
      int val;
      ListNode *next;
      ListNode() 
         : val(0), next(nullptr) {}
      ListNode(int x) 
         : val(x), next(nullptr) {}
      ListNode(int x, ListNode *next) 
         : val(x), next(next) {}
  };

And I want to sum two link list using recursive I am not sure but I guess it is tail recursive

Input: l1 = [2,4,3], l2 = [5,6,4]

Output: [7,0,8]

Explanation: 342 + 465 = 807.

ListNode* addTwoNumbers(ListNode* l1, ListNode* l2, int carry = 0,ListNode *result = nullptr) {
        
        int n1 = l1 != nullptr ? l1->val : 0;
        int n2 = l2 != nullptr ? l2->val : 0;
        
        int val = (n1 + n2 + carry) % 10;
        
        if(result == nullptr){
            result = new ListNode(val);
        }else{
            result->next = new ListNode(val);
            result = result->next;
        }
            
        result = addTwoNumbers(l1->next != nullptr ? l1->next : nullptr,
                               l2->next != nullptr ? l2->next : nullptr, 
                               (n1 + n2 + carry) - 10,result);
        return result;

    }

But I am getting an run time error. I can not see what is wrong,It should be work

Thank for your all answers.