Repository: youtube-dl
Issue: "Could not send HEAD request to https://learn.miguelgrinberg.com/watch/mega-tutorial/ch01.html: HTTP Error 500: INTERNAL SERVER ERROR"
Labels: site-support-request,account-needed

## Please follow the guide below

- You will be asked some questions and requested to provide some information, please read them **carefully** and answer honestly
- Put an `x` into all the boxes [ ] relevant to your *issue* (like this: `[x]`)
- Use the *Preview* tab to see what your issue will actually look like

---

### Make sure you are using the *latest* version: run `youtube-dl --version` and ensure your version is *2018.03.03*. If it's not, read [this FAQ entry](https://github.com/rg3/youtube-dl/blob/master/README.md#how-do-i-update-youtube-dl) and update. Issues with outdated version will be rejected.
- [x] I've **verified** and **I assure** that I'm running youtube-dl **2018.03.03**
```
$ youtube-dl --version
2018.03.03
```

### Before submitting an *issue* make sure you have:
- [x] At least skimmed through the [README](https://github.com/rg3/youtube-dl/blob/master/README.md), **most notably** the [FAQ](https://github.com/rg3/youtube-dl#faq) and [BUGS](https://github.com/rg3/youtube-dl#bugs) sections
- [x] [Searched](https://github.com/rg3/youtube-dl/search?type=Issues) the bugtracker for similar issues including closed ones
- [x] Checked that provided video/audio/playlist URLs (if any) are alive and playable in a browser

### What is the purpose of your *issue*?
- [ ] Bug report (encountered problems with youtube-dl)
- [x] Site support request (request for adding support for a new site)
- [ ] Feature request (request for a new functionality)
- [ ] Question
- [ ] Other

---

### The following sections concretize particular purposed issues, you can erase any section (the contents between triple ---) not applicable to your *issue*

---

### If the purpose of this *issue* is a *site support request* please provide all kinds of example URLs support for which should be included (replace following example URLs by **yours**):
- Single video: https://www.youtube.com/watch?v=BaW_jenozKc
- Single video: https://youtu.be/BaW_jenozKc
- Playlist: https://www.youtube.com/playlist?list=PL4lCao7KL_QFVb7Iudeipvc2BCavECqzc

Note that **youtube-dl does not support sites dedicated to [copyright infringement](https://github.com/rg3/youtube-dl#can-you-add-support-for-this-anime-video-site-or-site-which-shows-current-movies-for-free)**. In order for site support request to be accepted all provided example URLs should not violate any copyrights.

---

Hi - 

Could you add support for this site, which hosts its videos on Vimeo's streaming platform? The site requires a subscription.

Sample URLs are as follows:

 * https://learn.miguelgrinberg.com/watch/mega-tutorial/ch01.html
 * https://learn.miguelgrinberg.com/watch/mega-tutorial/ch02.html
...and so on, up to:
 * https://learn.miguelgrinberg.com/watch/mega-tutorial/ch23.html

Authenticated users can play videos at those URLs in a browser. Attempting to fetch videos from any of those URLs using `youtube-dl` fails with the error **ERROR: Unable to download webpage: HTTP Error 500: INTERNAL SERVER ERROR (caused by HTTPError());** despite providing credentials on the command line.

The full output from a verbose `youtube-dl` invocation follows:

```
$ youtube-dl --verbose -u PRIVATE https://learn.miguelgrinberg.com/watch/mega-tutorial/ch01.html
```
```
[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: [u'--verbose', u'-u', u'PRIVATE', u'https://learn.miguelgrinberg.com/watch/mega-tutorial/ch01.html']
Type account password and press [Return]: 
[debug] Encodings: locale UTF-8, fs UTF-8, out UTF-8, pref UTF-8
[debug] youtube-dl version 2018.03.03
[debug] Python version 2.7.14 (CPython) - Linux-4.13.0-36-generic-x86_64-with-Ubuntu-17.10-artful
[debug] exe versions: ffmpeg 3.3.4-2, ffprobe 3.3.4-2, rtmpdump 2.4
[debug] Proxy map: {}
[generic] ch01: Requesting header
WARNING: Could not send HEAD request to https://learn.miguelgrinberg.com/watch/mega-tutorial/ch01.html: HTTP Error 500: INTERNAL SERVER ERROR
[generic] ch01: Downloading webpage
ERROR: Unable to download webpage: HTTP Error 500: INTERNAL SERVER ERROR (caused by HTTPError()); please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; see  https://yt-dl.org/update  on how to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.
  File "/usr/local/lib/python2.7/dist-packages/youtube_dl/extractor/common.py", line 519, in _request_webpage
    return self._downloader.urlopen(url_or_request)
  File "/usr/local/lib/python2.7/dist-packages/youtube_dl/YoutubeDL.py", line 2199, in urlopen
    return self._opener.open(req, timeout=self._socket_timeout)
  File "/usr/lib/python2.7/urllib2.py", line 435, in open
    response = meth(req, response)
  File "/usr/lib/python2.7/urllib2.py", line 548, in http_response
    'http', request, response, code, msg, hdrs)
  File "/usr/lib/python2.7/urllib2.py", line 473, in error
    return self._call_chain(*args)
  File "/usr/lib/python2.7/urllib2.py", line 407, in _call_chain
    result = func(*args)
  File "/usr/lib/python2.7/urllib2.py", line 556, in http_error_default
    raise HTTPError(req.get_full_url(), code, msg, hdrs, fp)
```
Thank you for taking the time to look at this!