What causes "Unable to log in" in ytdl-org/youtube-dl?

Update youtube-dl / yt-dlp to the latest release — login-response schema changes are among the most frequently patched extractor bugs.

ytdl-org/youtube-dl · error · ExtractorError

Unable to log in

Error message

Unable to log in

What it means

PornHubBaseIE._login raises ExtractorError('Unable to log in') — with no reason text — when the login AJAX response has success != '1' AND the response JSON contains no 'message' key. This is the fallback branch: the site rejected the login but gave no explanation the extractor can surface. It is not marked expected=True, so it presents as an unexpected login failure.

Source

Thrown at youtube_dl/extractor/pornhub.py:118

            'https://www.%s/front/authenticate' % host, None,
            'Logging in to %s' % site,
            data=urlencode_postdata(login_form),
            headers={
                'Content-Type': 'application/x-www-form-urlencoded; charset=UTF-8',
                'Referer': login_url,
                'X-Requested-With': 'XMLHttpRequest',
            })

        if response.get('success') == '1':
            self._logged_in = True
            return

        message = response.get('message')
        if message is not None:
            raise ExtractorError(
                'Unable to login: %s' % message, expected=True)

        raise ExtractorError('Unable to log in')


class PornHubIE(PornHubBaseIE):
    IE_DESC = 'PornHub and Thumbzilla'
    _VALID_URL = r'''(?x)
                    https?://
                        (?:
                            (?:[^/]+\.)?
                            %s
                            /(?:(?:view_video\.php|video/show)\?viewkey=|embed/)|
                            (?:www\.)?thumbzilla\.com/video/
                        )
                        (?P<id>[\da-z]+)
                    ''' % PornHubBaseIE._PORNHUB_HOST_RE
    _TESTS = [{
        'url': 'http://www.pornhub.com/view_video.php?viewkey=648719015',
        'md5': 'a6391306d050e4547f62b3f485dd9ba9',
        'info_dict': {

View on GitHub (pinned to 956b8c5855)

Solutions

Update youtube-dl / yt-dlp to the latest release — login-response schema changes are among the most frequently patched extractor bugs.
Skip password login entirely and authenticate via browser cookies (--cookies cookies.txt exported after a manual login).
If no login is actually required for the content, drop --username/--password and retry anonymously.
Capture the raw login response (e.g. with a debugging proxy) to see what the site actually returned, and report it upstream if malformed.

Example fix

# before
youtube_dl --username me --password secret URL

# after
youtube_dl --cookies cookies.txt URL

Defensive patterns

Strategy: fallback

Try / catch

try:
    ydl.extract_info(url)
except ExtractorError as e:
    if 'Unable to log in' in str(e):
        run_without_credentials(url)  # anonymous attempt

Prevention

Update the extractor first — schema drift is the usual cause of the no-message branch.
Keep browser-exported cookies as the primary auth path.
If content needs no login, run anonymously and skip the login path entirely.

When it happens

Trigger: The login endpoint returns JSON like {'success': '0'} with no 'message' field — typically when the response shape changed (new field names), the request was blocked by anti-bot middleware returning a bare failure, or a non-JSON/empty body was parsed into something without 'message'.

Common situations: Site-side API changes after a youtube-dl release (response schema drift); WAF/CDN challenges (Cloudflare) intercepting the login POST; expired extractor version; malformed responses from regional mirrors like thumbzilla sharing the login code path.

Related errors

AI-assisted analysis of ytdl-org/youtube-dl@956b8c5855 (2026-08-14). Data as JSON: /api/errors/18a7dcc7eb2b6d6b. Report an issue: GitHub.