How to make it run without internet connection? - what part of code keeps it from running?

Question

My RBPi zero has a spotty reception close to the door where it keeps monitoring registered phones on bluetooth and trigger the door opener. What are the options to make it work without/irregular wifi connection? What part of code keeps it from running?

There is no way to add a wifi repeater between the Pi and the router (no outlets). So either I improve wifi range on one of the two sides or change the code to make it internet-independent.

here is the code:

import automationhat
import bluetooth
import time
import sys
import telegram

bot = telegram.Bot(token='xx')


# Import Adafruit IO MQTT client.
from Adafruit_IO import MQTTClient


# Set to your Adafruit IO key & username below.
ADAFRUIT_IO_KEY      = 'xx'
ADAFRUIT_IO_USERNAME = 'xx'

# Define callback functions which will be called when certain events happen.
def connected(client):
    # Connected function will be called when the client is connected to Adafruit IO.

    print('Connected to Adafruit IO!  Listening for LockReg changes...')
    # Subscribe to changes on a feed named LockReg.
    client.subscribe('LockReg')

def disconnected(client):
    # Disconnected function will be called when the client disconnects.
    print('Disconnected from Adafruit IO!')
    sys.exit(1)

def message(client, feed_id, payload, retain):
    # Message function will be called when a subscribed feed has a new value.
    # The feed_id parameter identifies the feed, and the payload parameter has
    # the new value.
    print('Feed {0} received new value: {1}'.format(feed_id, payload))

# Create an MQTT client instance.
client = MQTTClient(ADAFRUIT_IO_USERNAME, ADAFRUIT_IO_KEY)

# Setup the callback functions defined above.
client.on_connect    = connected
client.on_disconnect = disconnected
client.on_message    = message



PHONES = ['xxxxxxxxxxxx']


while True:

    print "Checking " + time.strftime("%a, %d %b %Y %H:%M:%S", time.gmtime())

    for device in PHONES:
            result = bluetooth.lookup_name(device, timeout=5)
            if (result != None):
                    # Connect to the Adafruit IO server.
                    client.connect()
                    print('Door unlocked. Nearby: %s (%s)' % (result, device))
                    client.publish('lock.reg', result)
                    automationhat.relay.one.on()
                    time.sleep(1)
                    automationhat.relay.one.off()
                    bot.sendMessage(-269345557, result)
                    time.sleep(300)
            else:
                    print "User out of range"
                    print('Door locked: No Bluetooth device detected. ' )
    time.sleep(6)