Life, the Universe, and Everything. Whats wrong with my code?

Can someone look at the below code and explain to me what is wrong. I have ran the problems set input and expected output on my machine and it returns exactly how it should. I even account for strings and numbers larger than two digits.

Thanks!

using System;
using System.Collections.Generic;
 
namespace RefreshingSkills
{
   public static class Program
   {
 
      // Method To Check String Value For Contains Integer
      public static bool IsInteger(this string s)
      {
         if (String.IsNullOrEmpty(s))
         {
            return false;
         }
 
         int i;
         return Int32.TryParse(s, out i);
      }
 
      private static void Main(string[] args)
      {
         // Prevents Non Zero Exit Code Error
         try
         {
            // Stores The Value Of User Input
            List<int> number = new List<int>();
            string userInput;
 
            Console.WriteLine("Enter Numbers:");
 
            // Loop To Allow User Input Of Numbers
            do
            {
               userInput = Console.ReadLine();
 
               if ((userInput.Length > 2 || !IsInteger(userInput)) && userInput.Length != 0)
               {
                  Console.WriteLine("Enter a two digit number.");
               }
               else if (userInput.Length != 0 && IsInteger(userInput))
               {
                  number.Add(Convert.ToInt32(userInput));
               }
            } while (userInput.Length != 0);
 
            Console.WriteLine();
            Console.WriteLine("Output:");
 
            // Loop To Output Numbers To The Console
            foreach (var item in number)
            {
               if (item != 42)
                  Console.WriteLine(item);
               else
                  break;
 
            }
 
            // Hold Console App
            Console.ReadLine();
         }
         catch (Exception e)
         {
            return;
         }
         
      }
   }
}