title: (Installing Python 3.6.1) SSLError: SSL: TLSV1_ALERT_UNKNOWN_CA tlsv1 alert unknown ca
body: <p>I'm trying to install Python 3.6 from source on Ubuntu 16.10. </p>
  
  <pre><code>make test
  </code></pre>
  
  <p>when I make test, the installation raises an error saying..</p>
  
  <pre><code>======================================================================
  ERROR: test_logincapa_with_client_certfile (test.test_imaplib.RemoteIMAP_SSLTest)
  ----------------------------------------------------------------------
  Traceback (most recent call last):
    File "/home/anderson/Downloads/Python-3.6.1/Lib/test/test_imaplib.py", line 973, in test_logincapa_with_client_certfile
      certfile=CERTFILE)
    File "/home/anderson/Downloads/Python-3.6.1/Lib/imaplib.py", line 1280, in __init__
      IMAP4.__init__(self, host, port)
    File "/home/anderson/Downloads/Python-3.6.1/Lib/imaplib.py", line 197, in __init__
      self.open(host, port)
    File "/home/anderson/Downloads/Python-3.6.1/Lib/imaplib.py", line 1293, in open
      IMAP4.open(self, host, port)
    File "/home/anderson/Downloads/Python-3.6.1/Lib/imaplib.py", line 294, in open
      self.sock = self._create_socket()
    File "/home/anderson/Downloads/Python-3.6.1/Lib/imaplib.py", line 1285, in _create_socket
      server_hostname=self.host)
    File "/home/anderson/Downloads/Python-3.6.1/Lib/ssl.py", line 401, in wrap_socket
      _context=self, _session=session)
    File "/home/anderson/Downloads/Python-3.6.1/Lib/ssl.py", line 808, in __init__
      self.do_handshake()
    File "/home/anderson/Downloads/Python-3.6.1/Lib/ssl.py", line 1061, in do_handshake
      self._sslobj.do_handshake()
    File "/home/anderson/Downloads/Python-3.6.1/Lib/ssl.py", line 683, in do_handshake
      self._sslobj.do_handshake()
  ssl.SSLError: [SSL: TLSV1_ALERT_UNKNOWN_CA] tlsv1 alert unknown ca (_ssl.c:749)
  
  ======================================================================
  ERROR: test_logincapa_with_client_ssl_context (test.test_imaplib.RemoteIMAP_SSLTest)
  ----------------------------------------------------------------------
  Traceback (most recent call last):
    File "/home/anderson/Downloads/Python-3.6.1/Lib/test/test_imaplib.py", line 979, in test_logincapa_with_client_ssl_context
      self.host, self.port, ssl_context=self.create_ssl_context())
    File "/home/anderson/Downloads/Python-3.6.1/Lib/imaplib.py", line 1280, in __init__
      IMAP4.__init__(self, host, port)
    File "/home/anderson/Downloads/Python-3.6.1/Lib/imaplib.py", line 197, in __init__
      self.open(host, port)
    File "/home/anderson/Downloads/Python-3.6.1/Lib/imaplib.py", line 1293, in open
      IMAP4.open(self, host, port)
    File "/home/anderson/Downloads/Python-3.6.1/Lib/imaplib.py", line 294, in open
      self.sock = self._create_socket()
    File "/home/anderson/Downloads/Python-3.6.1/Lib/imaplib.py", line 1285, in _create_socket
      server_hostname=self.host)
    File "/home/anderson/Downloads/Python-3.6.1/Lib/ssl.py", line 401, in wrap_socket
      _context=self, _session=session)
    File "/home/anderson/Downloads/Python-3.6.1/Lib/ssl.py", line 808, in __init__
      self.do_handshake()
    File "/home/anderson/Downloads/Python-3.6.1/Lib/ssl.py", line 1061, in do_handshake
      self._sslobj.do_handshake()
    File "/home/anderson/Downloads/Python-3.6.1/Lib/ssl.py", line 683, in do_handshake
      self._sslobj.do_handshake()
  ssl.SSLError: [SSL: TLSV1_ALERT_UNKNOWN_CA] tlsv1 alert unknown ca (_ssl.c:749)
  
  ----------------------------------------------------------------------
  Ran 95 tests in 21.126s
  
  FAILED (errors=2)
  test test_imaplib failed
  1 test failed again:
      test_imaplib
  
  Total duration: 3 min 9 sec
  Tests result: FAILURE
  Makefile:1018: recipe for target 'test' failed
  make: *** [test] Error 1
  </code></pre>
  
  <p>what's the problem?</p>