binary > T does not define this operator or a conversion to a type acceptable to the predefined operator

I am implementing a generic doubly linked list and am getting an error due to the > and < operators. Can anyone help me out?

Note: I am not allowed to use any STL functions

typename SortedList<T>::iterator SortedList<T>::insert(const T& data) {
    iterator it = begin();

    if (head_->next_ == tail_) {
        Node* newNode = new Node(data, tail_, head_);
        head_->next_ = newNode;
        tail_->prev_ = newNode;
        it.curr_ = newNode;
        ++size_;
        return it;
    }
    else {
        while (it != end()) {
            if ((*it < data) && (*it > data || it.curr_->next_ == tail_)) { // this line is giving me error
                Node* newNode = new Node(data, it.curr_->next_, it.curr_);
                it.curr_->next_->prev_ = newNode;
                it.curr_->next_ = newNode;
                it.curr_ = newNode;
                ++size_;
                return it;
            }
            it++;
        }
    }
}