conda update and conda install throws error with traceback to requests\adapters.py conn = self.get_connection(request.url, proxies)

Anaconda is able to use Requests to update or install packages from my Windows 10 Enterprise desktop environment, but throws an unexpected error in my Windows Server 2022 Standard environment. 

## Expected Result

With the below proxy settings in .condarc file in the Windows environment, conda update or conda install packages work. For example:
```
conda update conda 
conda -c conda-forge fuzzywuzzy

```
## Actual Result

In the server environment, using same .condarc file, if I run any conda update or install command, I get the following error:

 ERROR REPORT 
    Traceback (most recent call last):
      File "C:\Users\dyer01\Anaconda3\lib\site-packages\requests\adapters.py", line 412, in send
        conn = self.get_connection(request.url, proxies)
      File "C:\Users\dyer01\Anaconda3\lib\site-packages\requests\adapters.py", line 309, in get_connection
        proxy_manager = self.proxy_manager_for(proxy)
      File "C:\Users\dyer01\Anaconda3\lib\site-packages\requests\adapters.py", line 193, in proxy_manager_for
        manager = self.proxy_manager[proxy] = proxy_from_url(
      File "C:\Users\dyer01\Anaconda3\lib\site-packages\urllib3\poolmanager.py", line 536, in proxy_from_url
        return ProxyManager(proxy_url=url, **kw)
      File "C:\Users\dyer01\Anaconda3\lib\site-packages\urllib3\poolmanager.py", line 480, in __init__
        raise ProxySchemeUnknown(proxy.scheme)
    urllib3.exceptions.ProxySchemeUnknown: Proxy URL had no scheme, should start with http:// or https://

   During handling of the above exception, another exception occurred:

   Traceback (most recent call last):
      File "C:\Users\dyer01\Anaconda3\lib\site-packages\conda\exceptions.py", line 1079, in __call__
        return func(*args, **kwargs)
      File "C:\Users\dyer01\Anaconda3\lib\site-packages\conda\cli\main.py", line 84, in _main
        exit_code = do_call(args, p)
      File "C:\Users\dyer01\Anaconda3\lib\site-packages\conda\cli\conda_argparse.py", line 83, in do_call
        return getattr(module, func_name)(args, parser)
      File "C:\Users\dyer01\Anaconda3\lib\site-packages\conda\cli\main_install.py", line 20, in execute
        install(args, parser, 'install')
      File "C:\Users\dyer01\Anaconda3\lib\site-packages\conda\cli\install.py", line 261, in install
        unlink_link_transaction = solver.solve_for_transaction(
      File "C:\Users\dyer01\Anaconda3\lib\site-packages\conda\core\solve.py", line 114, in solve_for_transaction
        unlink_precs, link_precs = self.solve_for_diff(update_modifier, deps_modifier,
      File "C:\Users\dyer01\Anaconda3\lib\site-packages\conda\core\solve.py", line 157, in solve_for_diff
        final_precs = self.solve_final_state(update_modifier, deps_modifier, prune, ignore_pinned,
      File "C:\Users\dyer01\Anaconda3\lib\site-packages\conda\core\solve.py", line 262, in solve_final_state
        ssc = self._collect_all_metadata(ssc)
      File "C:\Users\dyer01\Anaconda3\lib\site-packages\conda\common\io.py", line 88, in decorated
        return f(*args, **kwds)
      File "C:\Users\dyer01\Anaconda3\lib\site-packages\conda\core\solve.py", line 425, in _collect_all_metadata
        index, r = self._prepare(prepared_specs)
      File "C:\Users\dyer01\Anaconda3\lib\site-packages\conda\core\solve.py", line 1020, in _prepare
        reduced_index = get_reduced_index(self.prefix, self.channels,
      File "C:\Users\dyer01\Anaconda3\lib\site-packages\conda\core\index.py", line 288, in get_reduced_index
        new_records = SubdirData.query_all(spec, channels=channels, subdirs=subdirs,
      File "C:\Users\dyer01\Anaconda3\lib\site-packages\conda\core\subdir_data.py", line 140, in que-ry_all
        result = tuple(concat(executor.map(subdir_query, channel_urls)))
      File "C:\Users\dyer01\Anaconda3\lib\concurrent\futures\_base.py", line 608, in result_iterator
        yield fs.pop().result()
      File "C:\Users\dyer01\Anaconda3\lib\concurrent\futures\_base.py", line 445, in result
        return self.__get_result()
      File "C:\Users\dyer01\Anaconda3\lib\concurrent\futures\_base.py", line 390, in __get_result
        raise self._exception
      File "C:\Users\dyer01\Anaconda3\lib\concurrent\futures\thread.py", line 52, in run
        result = self.fn(*self.args, **self.kwargs)
      File "C:\Users\dyer01\Anaconda3\lib\site-packages\conda\core\subdir_data.py", line 132, in <lambda>
        subdir_query = lambda url: tuple(SubdirData(Channel(url), repodata_fn=repodata_fn).query(
      File "C:\Users\dyer01\Anaconda3\lib\site-packages\conda\core\subdir_data.py", line 145, in query
        self.load()
      File "C:\Users\dyer01\Anaconda3\lib\site-packages\conda\core\subdir_data.py", line 210, in load
        _internal_state = self._load()
      File "C:\Users\dyer01\Anaconda3\lib\site-packages\conda\core\subdir_data.py", line 375, in _load
        raw_repodata_str = fetch_repodata_remote_request(
      File "C:\Users\dyer01\Anaconda3\lib\site-packages\conda\core\subdir_data.py", line 701, in fetch_repodata_remote_request
        resp = session.get(join_url(url, filename), headers=headers, proxies=session.proxies,
      File "C:\Users\dyer01\Anaconda3\lib\site-packages\requests\sessions.py", line 555, in get
        return self.request('GET', url, **kwargs)
      File "C:\Users\dyer01\Anaconda3\lib\site-packages\requests\sessions.py", line 542, in request
        resp = self.send(prep, **send_kwargs)
      File "C:\Users\dyer01\Anaconda3\lib\site-packages\requests\sessions.py", line 655, in send
        r = adapter.send(request, **kwargs)
      File "C:\Users\dyer01\Anaconda3\lib\site-packages\requests\adapters.py", line 414, in send
        raise InvalidURL(e, request=request)
    requests.exceptions.InvalidURL: Proxy URL had no scheme, should start with http:// or https://

$ C:\Users\dyer01\Anaconda3\Scripts\conda-script.py install -c conda-forge fuzzywuzzy

  environment variables:
                 CIO_TEST=<not set>
        CONDA_DEFAULT_ENV=base
                CONDA_EXE=C:\Users\dyer01\Anaconda3\condabin\..\Scripts\conda.exe
               CONDA_EXES="C:\Users\dyer01\Anaconda3\condabin\..\Scripts\conda.exe"
             CONDA_PREFIX=C:\Users\dyer01\Anaconda3
    CONDA_PROMPT_MODIFIER=(base)
         CONDA_PYTHON_EXE=C:\Users\dyer01\Anaconda3\python.exe
               CONDA_ROOT=C:\Users\dyer01\Anaconda3
              CONDA_SHLVL=1
           CURL_CA_BUNDLE=<not set>
                 HOMEPATH=\
                     PATH=C:\Users\dyer01\Anaconda3;C:\Users\dyer01\Anaconda3\Library\mingw-w64\
                          bin;C:\Users\dyer01\Anaconda3\Library\usr\bin;C:\Users\dyer01\Anaconda
                          3\Library\bin;C:\Users\dyer01\Anaconda3\Scripts;C:\Users\dyer01\Anacon
                          da3\bin;C:\Users\dyer01\Anaconda3;C:\Users\dyer01\Anaconda3\Library\mi
                          ngw-w64\bin;C:\Users\dyer01\Anaconda3\Library\usr\bin;C:\Users\dyer01\
                          Anaconda3\Library\bin;C:\Users\dyer01\Anaconda3\Scripts;C:\Users\dyer0
                          1\Anaconda3\bin;C:\Users\dyer01\Anaconda3\condabin;C:\Users\dyer01\Ana
                          conda3;C:\Users\dyer01\Anaconda3\Library\mingw-w64\bin;C:\Users\dyer01
                          \Anaconda3\Library\usr\bin;C:\Users\dyer01\Anaconda3\Library\bin;C:\Us
                          ers\dyer01\Anaconda3\Scripts;C:\Windows\system32;C:\Windows;C:\Windows
                          \System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0;C:\Windows\S
                          ystem32\OpenSSH;C:\Program Files (x86)\Microsoft SQL
                          Server\150\DTS\Binn;C:\Program Files\Azure Data
                          Studio\bin;C:\Users\dyer01\AppData\Local\Microsoft\WindowsApps;.
             PSMODULEPATH=C:\Program Files\WindowsPowerShell\Modules;C:\Windows\system32\Windows
                          PowerShell\v1.0\Modules
       REQUESTS_CA_BUNDLE=<not set>
            SSL_CERT_FILE=<not set>

 active environment : base
 active env location : C:\Users\dyer01\Anaconda3
            shell level : 1
       user config file : C:\Users\dyer01\.condarc
 populated config files : C:\Users\dyer01\.condarc
          conda version : 4.10.3
 conda-build version : 3.21.6
         python version : 3.9.7.final.0
  virtual packages : __win=0=0
                          __archspec=1=x86_64
       base environment : C:\Users\dyer01\Anaconda3  (writable)
      conda av data dir : C:\Users\dyer01\Anaconda3\etc\conda
  conda av metadata url : None
           channel URLs : https://conda.anaconda.org/conda-forge/win-64
                          https://conda.anaconda.org/conda-forge/noarch
                          https://repo.anaconda.com/pkgs/main/win-64
                          https://repo.anaconda.com/pkgs/main/noarch
                          https://repo.anaconda.com/pkgs/r/win-64
                          https://repo.anaconda.com/pkgs/r/noarch
                          https://repo.anaconda.com/pkgs/msys2/win-64
                          https://repo.anaconda.com/pkgs/msys2/noarch
          package cache : C:\Users\dyer01\Anaconda3\pkgs
                          C:\Users\dyer01\.conda\pkgs
                          C:\Users\dyer01\AppData\Local\conda\conda\pkgs
       envs directories : C:\Users\dyer01\Anaconda3\envs
                          C:\Users\dyer01\.conda\envs
                          C:\Users\dyer01\AppData\Local\conda\conda\envs
               platform : win-64
             user-agent : conda/4.10.3 requests/2.26.0 CPython/3.9.7 Windows/10 Windows/10.0.20348
          administrator : False
             netrc file : None
           offline mode : False


## Reproduction Steps

Requests used in conda install or update work in one environment, but not in other.

Modifying the .condarc file (adding "http" and/or quotes and/or slashes and/or indents) fails to connect to proxy server.

Testing internet connection using Requests, as decribed [here](https://www.kite.com/python/answers/how-to-check-internet-connection-in-python), works in both environments.

## System Information

**Windows environment:**
{
  "chardet": {
    "version": "4.0.0"
  },
  "charset_normalizer": {
    "version": "2.0.4"
  },
  "cryptography": {
    "version": "3.4.8"
  },
  "idna": {
    "version": "3.3"
  },
  "implementation": {
    "name": "CPython",
    "version": "3.8.11"
  },
  "platform": {
    "release": "10",
    "system": "Windows"
  },
  "pyOpenSSL": {
    "openssl_version": "101010cf",
    "version": "21.0.0"
  },
  "requests": {
    "version": "2.27.1"
  },
  "system_ssl": {
    "version": "101010bf"
  },
  "urllib3": {
    "version": "1.26.7"
  },
  "using_charset_normalizer": false,
  "using_pyopenssl": true
}

**Server environment:**
{
  "chardet": {
    "version": "4.0.0"
  },
  "charset_normalizer": {
    "version": "2.0.4"
  },
  "cryptography": {
    "version": "3.4.8"
  },
  "idna": {
    "version": "3.2"
  },
  "implementation": {
    "name": "CPython",
    "version": "3.9.7"
  },
  "platform": {
    "release": "10",
    "system": "Windows"
  },
  "pyOpenSSL": {
    "openssl_version": "101010cf",
    "version": "21.0.0"
  },
  "requests": {
    "version": "2.26.0"
  },
  "system_ssl": {
    "version": "101010cf"
  },
  "urllib3": {
    "version": "1.26.7"
  },
  "using_charset_normalizer": false,
  "using_pyopenssl": true
}



You seem to have a proxy configured without an explicit scheme.

```
requests.exceptions.InvalidURL: Proxy URL had no scheme, should start with http:// or https://
```

Quoting from your report. Fix that and everything should be fine

Unfortunately, whenever I use the full scheme, I get the following error: 

Collecting package metadata (current_repodata.json): failed
ProxyError: Conda cannot proceed due to an error in your proxy configuration.
Check for typos and other configuration errors in any '.netrc' file in your home directory,
any environment variables ending in '_PROXY', and any other system-wide proxy
configuration settings.

In the windows environment, I was getting this same error until I removed the scheme, and it worked(s) fine.

I have tried all manner of changes to the .condarc file, including schemes, slashes, quotes, indents. Maybe there is still something I haven't thought of to try. This is what works in the windows environemnt:

```
proxy_servers:
  http: blah.ldd.rnk:8080
  https: blah.ldd.rnk:8080
```

I don't use conda so I can't help you fix this. I've told you what the issue is with requests. You should use stack overflow or a different conda support channel to figure out your other issues

Stack overflow advise says to do exactly what you suggest, but it never worked. After the pain I went through, in August last year, I even posted [the solution without the scheme](https://stackoverflow.com/questions/36729023/how-to-make-anaconda-work-behind-http-proxy-not-https/68724703#68724703), which has helped at least one person. I don't see any options but to raise it with conda, who may say it's not a conda issue either.

I was completing a report for conda, and made the following typo:
```
proxy_servers:
  http: http://rnkserv14.lra.rnk:8080
  https: http://rnkserv14.lra.rnk:8080
```
Note - the lack of 's' in the https: scheme. 

It works. I don't have anything to do with our proxy server, but I guess it is set up like this.