See alsobpo-30319: test_invalid_authentication()  of test_imaplib: ConnectionResetError: [Errno 54] Connection reset by peer on AMD64 FreeBSD 9.x 3.6.http://buildbot.python.org/all/builders/AMD64%20Windows8.1%20Non-Debug%203.6/builds/375/steps/test/logs/stdiotest_login_cram_md5 (test.test_imaplib.ThreadedNetworkedTestsSSL) ... creating serverserver createdADDR = ('127.0.0.1', 0)CLASS = <class 'test.test_imaplib.SecureTCPServer'>HDLR = <class 'test.test_imaplib.ThreadedNetworkedTests.test_login_cram_md5.<locals>.AuthHandler'>server runningSENT: b'* OK IMAP4rev1'GOT: b'PJGL0 CAPABILITY'SENT: b'* CAPABILITY IMAP4rev1 LOGINDISABLED AUTH=CRAM-MD5'SENT: b'PJGL0 OK CAPABILITY completed'GOT: b'PJGL1 AUTHENTICATE CRAM-MD5'SENT: b'+ PDE4OTYuNjk3MTcwOTUyQHBvc3RvZmZpY2UucmVzdG9uLm1jaS5uZXQ='GOT: b'dGltIGYxY2E2YmU0NjRiOWVmYTFjY2E2ZmZkNmNmMmQ5ZjMy'SENT: b'PJGL1 OK CRAM-MD5 successful'GOT: b'PJGL2 LOGOUT'SENT: b'* BYE IMAP4ref1 Server logging out'SENT: b'PJGL2 OK LOGOUT completed'waiting for serverdoneERROR======================================================================ERROR: test_login_cram_md5 (test.test_imaplib.ThreadedNetworkedTestsSSL)----------------------------------------------------------------------Traceback (most recent call last):  File "D:\buildarea\3.6.ware-win81-release\build\lib\test\support\__init__.py", line 2035, in decorator    return func(*args)  File "D:\buildarea\3.6.ware-win81-release\build\lib\test\test_imaplib.py", line 796, in test_login_cram_md5    self.assertEqual(ret, "OK")  File "D:\buildarea\3.6.ware-win81-release\build\lib\contextlib.py", line 89, in __exit__    next(self.gen)  File "D:\buildarea\3.6.ware-win81-release\build\lib\test\test_imaplib.py", line 567, in reaped_pair    client.logout()  File "D:\buildarea\3.6.ware-win81-release\build\lib\imaplib.py", line 622, in logout    self.shutdown()  File "D:\buildarea\3.6.ware-win81-release\build\lib\imaplib.py", line 320, in shutdown    self.sock.shutdown(socket.SHUT_RDWR)  File "D:\buildarea\3.6.ware-win81-release\build\lib\ssl.py", line 1040, in shutdown    socket.shutdown(self, how)OSError: [WinError 10022] An invalid argument was supplied----------------------------------------------------------------------Ran 95 tests in 6.890sFAILED (errors=1, skipped=4)test test_imaplib failed