Cannot establish MQTT SSL connection

[manos.compass]

Hi everyone, this is my first attempt to publish with MQTT & SSL on test.mosquitto.org. I have zero experience in python. I do have some experience in Ruby and in Ruby on Rails. I tried non-ssl and it worked fine.
Please have a look at the code. My goal is to use all three keys in the ssl_params dictionary. However i currently need only two for connecting to the mosquitto server. I generated the certificate file & key at the mosquitto website see here: https://test.mosquitto.org/ssl/ . I have uploaded the mqtt.py file in /flash/cert dir via ftp. I have tried both 8883 & 8884 port. No luck.
After executing the code in atom editor i get the following error:

>>> Running mqtt unenqrypted.py
>>>
>>>
Connecting to WiFi network 'TOTOLINK 2.4G (1)'
Connecting to MQTT server...
Traceback (most recent call last):
File "<stdin>", line 50, in <module>
File "/flash/lib/mqtt.py", line 69, in connect
ValueError: invalid argument(s) value
>
Pycom MicroPython 1.20.2.rc6 [v1.11-01f49f7] on 2020-02-28; FiPy with ESP32
Pybytes Version: 1.3.1
Type "help()" for more information.
>>>
>>>

from mqtt import MQTTClient
from network import WLAN
import machine
import time
import ussl

def sub_cb(topic, msg):
   print(msg)

ctr = 0
ssid = "TOTOLINK 2.4G (1)"
ip = "192.168.2.100"
g_ip = "192.168.2.1"
mask = "255.255.255.0"
password = "XXXXXXXXXXXXXXXX"

device_id = "mydevice-AF4Wd24F2S"
mqtt_url = "test.mosquitto.org" 
mqtt_user = ""
mqtt_pass = ""
mqtt_port = 8884

#ssl_params = {'cert_reqs': ssl.CERT_REQUIRED, 'ca_certs': 'pycom/ca.pem', 'keyfile': '/flash/cert/client.pem', 'certfile': '/flash/cert/client.pem'}
ssl_params = {'cert_reqs': ussl.CERT_REQUIRED, 'keyfile': '/flash/cert/client.key', 'certfile': '/flash/cert/client.pem'}

wlan = WLAN(mode=WLAN.STA)
# go for fixed IP settings (IP, Subnet, Gateway, DNS)
wlan.ifconfig(config=(ip, mask, g_ip, g_ip))
wlan.scan()     # scan for available networks
wlan.connect(ssid=ssid, auth=(WLAN.WPA2, password))

print("Connecting to WiFi network '" + ssid + "'")
while not wlan.isconnected():
    machine.idle()

print("Connecting to MQTT server...")
client = MQTTClient(
    device_id,
    mqtt_url,
    port=mqtt_port,
    keepalive=60,
    ssl=True,
    ssl_params=ssl_params
)

client.set_callback(sub_cb)
status = client.connect()

if status == 0:
    print("Success\n")
else:
    print("Failure\n")

while True:
    print("Sun is rising...")
    client.publish(topic="manos/status/sun", msg="RISE")
    time.sleep(1)
    print("Sun is setting...")
    client.publish(topic="manos/status/sun", msg="SET")
    client.check_msg()
    time.sleep(1)

Unfortunately the docs have only got a non-enqrypted connection setup.
I just don't get it... Why don't they have more code examples?
Can anybody help me get this done?

Regards to all

[gldoug]

I'm going to be working on something similar over the next little while, so if you do make progress, I would be interested to read about it.

In my arduino environment, the 'secure' connection happens when you're starting the wifi... you either start the wifi client with or without 'security'....