title: Invalid value for encryptedTicket parameter
body: <p>I recently modified the login for my companies eComm site to have a "Keep me logged in" feature.  The primary change was to make the forms authentication cookie persistent for these users.</p>
  
  <p>After the change was released I started seeing this exeception in my logs: </p>
  
  <pre><code>Invalid value for 'encryptedTicket' parameter
  at System.Web.Security.FormsAuthentication.Decrypt(String encryptedTicket)
  </code></pre>
  
  <p>The problem seems to be user agent specific.  The only user agents the error has been recorded for are:</p>
  
  <ul>
  <li><p>Mozilla/5.0 (iPad; U; CPU OS 4_3_3 like Mac OS X; en-us) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8J2 Safari/6533.18.5</p></li>
  <li><p>eTailInsights Tag Identifier/1.0</p></li>
  </ul>
  
  <p>I have an iPad with the configuration listed above.  The first login attempt works.  But closing the browser and going back to the site, thus using the persistent cookie, causes the error.  </p>
  
  <p>The behavior is also inconsistent across environments.  It works fine against my local machine and test server, but fails on production.  Which makes it difficult to troubleshoot.</p>
  
  <p>Other versions of iOS/Safari can login fine.</p>
  
  <p>Searching for this error turned up several <a href="http://manual.aspdotnetstorefront.com/p-1635-invalid-value-for-encryptedticket-parameter-in-internet-explorer-10-ie10.aspx" rel="nofollow noreferrer">references</a> to a problem with web forms and newer browser versions.  This does not seem consistent with my scenario though.  I'm not seeing errors for new browsers and my site is MVC.</p>
  
  <p>I found one <a href="https://stackoverflow.com/questions/15921451/asp-net-web-forms-gives-ticket-error-on-ipads">question</a> similar to mine, but with no answer.</p>
  
  <p>Anybody know what is happening here?</p>