Reverse a sublist of a linked list

Question

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode() {}
 *     ListNode(int val) { this.val = val; }
 *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
 * }
 */
class Solution {
    public ListNode reverseBetween(ListNode head, int left, int right) {
        if(head.next==null){
            return head;
        }
        if(left==right){
            return head;
        }
      ListNode dummy=new ListNode();
        dummy.next=head;
        ListNode prevNode=dummy;
        ListNode currNode=head;
        
        
        for(int i=1;i<left;i++){
            prevNode=currNode;
            currNode=currNode.next;
            
        }
        
        for(int i=1;i<=(right-left);i++){
             ListNode nextNode=currNode.next;
            prevNode.next=nextNode;``
            currNode.next=nextNode.next;
            nextNode.next=prevNode.next;            
            
            
        }
        
        return dummy.next;
}}

It is a question of reversing sublist from Leetcode.Can anyone please tell me why it is showing "found cycle in code"??I dont know why it showing this error.Please explain.