title: Error 500 when trying to subscribe to ical calendar feed in Yahoo Calendar
body: <p>I am trying to subscribe to an ical feed through Yahoo Calendar using a URL in the following format: <code>https://calendar.yahoo.com/subscribe?ics={__ICS_FEED_URL__}&amp;name={__NAME__}</code>. After accessing that URL, Yahoo presents me with a dialog box pre-populated with the URL to the feed and the name. After hitting "OK" a dialog box follows soon after with a 500 error.</p>
  
  <p>Digging around in Chrome Console reveals the following message in the Chrome Console from the call used by Yahoo to subscribe to the calendar: <code>{"calendarError":{"lang":"en-US","description":"Failed to create new folder","detail":"Not Applicable","code":0}}</code>.</p>
  
  <h3>Example ical feed</h3>
  
  <pre><code>BEGIN:VCALENDAR
  VERSION:2.0
  PRODID:-//Lanzar Group//SendCalendar//EN
  NAME:Sample: Walking Tours
  X-WR-CALNAME:Sample: Walking Tours
  BEGIN:VEVENT
  UID:MKq2333pN8zH6RCeC@sendcalendar.com
  SEQUENCE:0
  DTSTAMP:20160829T062543Z
  DTSTART:20160901T100000Z
  DTEND:20160901T120000Z
  SUMMARY:Sample Event: Visiting the Eiffel Tower
  LOCATION:Champ de Mars\, 5 Avenue Anatole France\, 75007 Paris\, France
  DESCRIPTION:The Eiffel Tower is one of the most recognizable buildings in the world\, so of course it is an important part of any trip to Paris. Since its completion over 100 years ago\, it has become a symbol of Paris. Although it is no longer the tallest building in the world\, a title it held for 41 years. it still dominates the skyline of the City of Lights. It’s also very popular\, here are some tips for making your visit go smoothly.
  ORGANIZER;CN="John Doe":mailto:john.doe@example.com
  END:VEVENT
  END:VCALENDAR
  </code></pre>
  
  <h3>Example HTTP response headers for the above feed</h3>
  
  <pre><code>Server: nginx/1.11.3
  Date: Mon, 29 Aug 2016 06:28:06 GMT
  Content-Type: text/calendar; charset=utf-8
  Connection: keep-alive
  Cache-Control: no-store
  Pragma: no-cache
  Access-Control-Allow-Origin: *
  Access-Control-Allow-Headers: Origin, X-Requested-With, Content-Type, Accept
  Content-Disposition: attachment; filename=sample-walking-tours.ics
  Vary: Accept-Encoding
  Strict-Transport-Security: max-age=31536000
  </code></pre>
  
  <h3>URL to reproduce the problem</h3>
  
  <p><a href="https://calendar.yahoo.com/subscribe?ics=https://staging.sendcalendar.com/api/calendar/NZQdHTbmX88cFsm8K/icalfeed&amp;name=Sample:%20Walking%20Tours">https://calendar.yahoo.com/subscribe?ics=https://staging.sendcalendar.com/api/calendar/NZQdHTbmX88cFsm8K/icalfeed&amp;name=Sample:%20Walking%20Tours</a></p>
  
  <p>What is the cause of this problem? More importantly, what do I need to change to solve it? I have found no documentation online, and have not seen any similar reports of this issue.</p>