title: Proxies don't connect, returns a httpsconnection error
body: <p>I have this issue with multiple programs that I created which use proxies. I'm using free proxies, which is probably the cause of the errors. But as  I wanted to be sure of it I'm asking for a definitive answer. Down below I added the way of which I configure the proxies in my code and the errors that I get back when making an https request.</p>
  <pre><code>    with open('external/proxies.txt', 'r') as proxyFile:
          proxyList = [line.strip() for line in proxyFile]      
      
      def proxies(self):
          self.choice = random.choice(self.proxyList)
          return {
            'http': f'http://{self.choice}',
            'https': f'http://{self.choice}'}
  
      def somefunc(self):
          self.proxy = self.proxies()
          r = requests.get('..', proxies=self.proxy)
  </code></pre>
  <p>Errors:</p>
  <pre><code>HTTPSConnectionPool(host='public-ubiservices.ubi.com', port=443): Max retries exceeded with url: /v3/profiles/sessions (Caused by ProxyError('Cannot connect to proxy.', OSError('Tunnel connection failed: 503 Service Temporarily Unavailable')))
  HTTPSConnectionPool(host='public-ubiservices.ubi.com', port=443): Max retries exceeded with url: /v3/profiles/sessions (Caused by ProxyError('Cannot connect to proxy.', ConnectionResetError(10054, 'An existing connection was forcibly closed by the remote host', None, 10054, None)))
  HTTPSConnectionPool(host='public-ubiservices.ubi.com', port=443): Max retries exceeded with url: /v3/profiles/sessions (Caused by ProxyError('Cannot connect to proxy.', RemoteDisconnected('Remote end closed connection without response')))
  </code></pre>