I'm using Adafruit IO switches to turn my nodeMCU lights ON and OFF. The following code works but for a limited period of time. 5 minutes after the connection into Adafruit IO it seems the client tries to reconnect and if this happens I lose my switch funcionality at my adafruit dashboard. Either if I try to turn on or off the LED on my dashboard, the nodeMCU does not responds accordingly. Here is the code used (I'm using micropython, pycharm and a Lolin v3 nodemcu)

from machine import Pin
import sys
import os
import network
from umqtt.robust import MQTTClient

random_num = int.from_bytes(os.urandom(3), 'little')
mqtt_client_id = bytes('client_' + str(random_num), 'utf-8')

ADAFRUIT_LINK = b'io.adafruit.com'
ADAFRUIT_USERNAME = b'rodrigo1120'
ADAFRUIT_KEY = b'AAAAAAAAAAAAAAAAAAAAAAAAAAAA'
ADAFRUIT_FEEDNAME1 = b'gpio16'
ADAFRUIT_FEEDNAME2 = b'gpio2'

ssid = "WIFIUSERNAME"
password = "WIFIPASSWORD"

client = MQTTClient(client_id= mqtt_client_id,
                    server= ADAFRUIT_LINK,
                    user=ADAFRUIT_USERNAME,
                    password=ADAFRUIT_KEY)

mqtt_feedname1 = bytes('{:s}/feeds/{:s}'.format(ADAFRUIT_USERNAME, ADAFRUIT_FEEDNAME1), 'utf-8')
mqtt_feedname2 = bytes('{:s}/feeds/{:s}'.format(ADAFRUIT_USERNAME, ADAFRUIT_FEEDNAME2), 'utf-8')


def connect_to_ap():
    wlan = network.WLAN(network.STA_IF)
    wlan.active(True)
    if not wlan.isconnected():
        print('Connecting to {}'.format(ssid))
        wlan.connect(ssid, password)
        while not wlan.isconnected():
            pass
    print('Credentials: ', wlan.ifconfig())
    try:
        client.connect()
    except Exception as e:
        print('Could not connect to MQTT Server {}{}'.format(type(e).__name__, e))


def callback_routine(feed, msg):
    print('Received Data from: feed={}, msg={}'.format(feed, msg))
    if ADAFRUIT_FEEDNAME1 in feed:
        action = str(msg, 'utf-8')
        if action == 'ON':
            pin16.value(0)
        else:
            pin16.value(1)
        print('Action: {}'.format(action))
    if ADAFRUIT_FEEDNAME2 in feed:
        action = str(msg, 'utf-8')
        if action == 'ON':
            pin2.value(0)
        else:
            pin2.value(1)
        print('Action: {}'.format(action))


pin16 = Pin(16, Pin.OUT)
pin2 = Pin(2, Pin.OUT)
pin16.value(1)
pin2.value(1)


def main():
    connect_to_ap()
    while True:
        client.set_callback(callback_routine)
        client.subscribe(mqtt_feedname1)
        client.subscribe(mqtt_feedname2)
        try:
            client.wait_msg()
        except KeyboardInterrupt:
            print('Ctrl+C pressed, exiting')
            client.disconnect()
            sys.exit()


if __name__ == '__main__':
    main()

Here is a picture of my serial monitor with this problem: (I took this picture 15 minutes after I stopped using the adafruit IO switches)