ytdl-org/youtube-dl · error · Socks5Error

all offered authentication methods were rejected

Error message

all offered authentication methods were rejected

What it means

Raised as Socks5Error(AUTH_NO_ACCEPTABLE) after the SOCKS5 method negotiation when the server replies with method 0xFF (no acceptable methods) or selects username/password auth while the client has no username/password configured. The connection is closed and the single message 'all offered authentication methods were rejected' is raised.

Source

Thrown at youtube_dl/socks.py:199

        packet = compat_struct_pack('!B', SOCKS5_VERSION)

        auth_methods = [Socks5Auth.AUTH_NONE]
        if self._proxy.username and self._proxy.password:
            auth_methods.append(Socks5Auth.AUTH_USER_PASS)

        packet += compat_struct_pack('!B', len(auth_methods))
        packet += compat_struct_pack('!{0}B'.format(len(auth_methods)), *auth_methods)

        self.sendall(packet)

        version, method = self._recv_bytes(2)

        self._check_response_version(SOCKS5_VERSION, version)

        if method == Socks5Auth.AUTH_NO_ACCEPTABLE or (
                method == Socks5Auth.AUTH_USER_PASS and (not self._proxy.username or not self._proxy.password)):
            self.close()
            raise Socks5Error(Socks5Auth.AUTH_NO_ACCEPTABLE)

        if method == Socks5Auth.AUTH_USER_PASS:
            username = self._proxy.username.encode('utf-8')
            password = self._proxy.password.encode('utf-8')
            packet = compat_struct_pack('!B', SOCKS5_USER_AUTH_VERSION)
            packet += self._len_and_data(username) + self._len_and_data(password)
            self.sendall(packet)

            version, status = self._recv_bytes(2)

            self._check_response_version(SOCKS5_USER_AUTH_VERSION, version)

            if status != SOCKS5_USER_AUTH_SUCCESS:
                self.close()
                raise Socks5Error(Socks5Error.ERR_GENERAL_FAILURE)

    def _setup_socks5(self, address):
        destaddr, port = address

View on GitHub (pinned to 956b8c5855)

Solutions

Include credentials in the proxy URL: --proxy 'socks5://user:pass@host:port'
URL-encode special characters in the password (@, :, /, #) when embedding them
Confirm the proxy account is active and the server accepts username/password auth (method 0x02)
If the proxy should be open, fix its configuration to also offer 'no auth' (0x00)

Example fix

# before
youtube-dl --proxy 'socks5://proxy.example.com:1080' URL
# after
youtube-dl --proxy 'socks5://alice:p%40ssword@proxy.example.com:1080' URL

Defensive patterns

Strategy: validation

Validate before calling

from urllib.parse import urlsplit

def socks_proxy_has_credentials(proxy_url):
    parts = urlsplit(proxy_url)
    return parts.scheme.startswith('socks5') and bool(parts.username) and bool(parts.password)

if opts['proxy'].startswith('socks5') and not socks_proxy_has_credentials(opts['proxy']):
    raise ValueError('this SOCKS5 proxy requires user:pass in the URL')

Try / catch

try:
    ydl.download([url])
except Exception as e:
    if 'all offered authentication methods were rejected' in str(e):
        # config problem, not transient: add credentials and run once more
        opts['proxy'] = 'socks5://%s:%s@host:1080' % (user, quoted_pass)
        ydl.download([url])

Prevention

Always embed user:pass for private SOCKS5 proxies: socks5://user:pass@host:port
URL-encode special characters in proxy passwords
Retry only after changing credentials — the same anonymous request will fail identically

When it happens

Trigger: Using --proxy socks5://host:port where the proxy requires username/password authentication but no credentials were embedded in the proxy URL; or a proxy configured to accept only auth methods the client did not offer.

Common situations: Paid/private SOCKS5 proxies that mandate auth; credentials present in a config elsewhere but not passed to youtube-dl; URL-encoding mistakes that strip the user:pass part of the proxy URL.

Understand the failure class

Authentication and authorization failures — expired tokens, bad credentials, and missing scopes.

Related errors

AI-assisted analysis of ytdl-org/youtube-dl@956b8c5855 (2026-08-14). Data as JSON: /api/errors/81cdb74db93f0c03. Report an issue: GitHub.