title: System.ArgumentNullException: 'String reference not set to an instance of a String. Parameter name: s'
body: <p>When i submit the registration form i get this error:</p>
  
  <blockquote>
    <p>System.ArgumentNullException: 'String reference not set to an instance of a String.
    Parameter name: s'</p>
  </blockquote>
  
  <p>it's coming form the hashing password class</p>
  
  <pre><code>public static class Crypto
  {
      public static string Hash(string value)
      {
          return Convert.ToBase64String(
              SHA256.Create()
                  .ComputeHash(Encoding.UTF8.GetBytes(value)));
      }
  }
  </code></pre>