504 Gateway Time-out

nginx/1.10.2

EMAIL_BACKEND = 'django.core.mail.backends.smtp.EmailBackend'
AUTH_USER_EMAIL_UNIQUE = True
EMAIL_HOST = 'smtp.yandex.ru'
EMAIL_PORT = 465
EMAIL_HOST_USER = 'my_mail'
EMAIL_HOST_PASSWORD = 'my_pass'
EMAIL_USE_TLS = True
DEFAULT_FROM_EMAIL = ''