[Kiwi 12.7] Sending test mail reports "certificate verify failed: unable to get local issuer certificate"

[sansanpetrov]

Description of problem

I am using official docker Kiwi-CE. I changed common.py file as it's described in manual to to set e-mail notifications.
My SMTP-server requires SSL.
Debug from command line like
docker exec -it kiwi_web /Kiwi/manage.py sendtestemail user1@example1.ru
gives report:
ssl.SSLCertVerificationError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1129)

But all certificates are installed (I use defaults in container) and https is running correctly.

Version or commit hash (if applicable)

Kiwi-CE (docker) v.12.7

Steps to Reproduce

1. Change common.py file to set e-mail configuration. Enable SSL.
2. Run test e-mail via docker (as described in manual).

Actual results

ssl.SSLCertVerificationError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1129)

Expected results

E-mail is received.

Additional info (Python traceback, logs, etc.)

Traceback (most recent call last):
File "/Kiwi/manage.py", line 12, in
execute_from_command_line(sys.argv)
File "/venv/lib64/python3.9/site-packages/django/core/management/init.py", line 442, in execute_from_command_line
utility.execute()
File "/venv/lib64/python3.9/site-packages/django/core/management/init.py", line 436, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/venv/lib64/python3.9/site-packages/django/core/management/base.py", line 412, in run_from_argv
self.execute(*args, **cmd_options)
File "/venv/lib64/python3.9/site-packages/django/core/management/base.py", line 458, in execute
output = self.handle(*args, **options)
File "/venv/lib64/python3.9/site-packages/django/core/management/commands/sendtestemail.py", line 35, in handle
send_mail(
File "/venv/lib64/python3.9/site-packages/django/core/mail/init.py", line 87, in send_mail
return mail.send()
File "/venv/lib64/python3.9/site-packages/django/core/mail/message.py", line 298, in send
return self.get_connection(fail_silently).send_messages([self])
File "/venv/lib64/python3.9/site-packages/django/core/mail/backends/smtp.py", line 127, in send_messages
new_conn_created = self.open()
File "/venv/lib64/python3.9/site-packages/django/core/mail/backends/smtp.py", line 85, in open
self.connection = self.connection_class(
File "/usr/lib64/python3.9/smtplib.py", line 1050, in init
SMTP.init(self, host, port, local_hostname, timeout,
File "/usr/lib64/python3.9/smtplib.py", line 255, in init
(code, msg) = self.connect(host, port)
File "/usr/lib64/python3.9/smtplib.py", line 341, in connect
self.sock = self._get_socket(host, port, self.timeout)
File "/usr/lib64/python3.9/smtplib.py", line 1057, in _get_socket
new_socket = self.context.wrap_socket(new_socket,
File "/usr/lib64/python3.9/ssl.py", line 501, in wrap_socket
return self.sslsocket_class._create(
File "/usr/lib64/python3.9/ssl.py", line 1041, in _create
self.do_handshake()
File "/usr/lib64/python3.9/ssl.py", line 1310, in do_handshake
self._sslobj.do_handshake()
ssl.SSLCertVerificationError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1129)