core: Connection to TP-Link LTE router fails with MR-6400 v5

The problem

Hello,

Login to TP-Link LTE router with the tplink_lte core integration fails at login time, preventing the associated SMS service to be instantiated.

Declared issue here with HA core 2022.6.6 but actually never worked even with pre-2022. My TP-Link LTE router is MR6400, running firmware v5.

Error doing job: Task exception was never retrieved
Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/components/tplink_lte/__init__.py", line 122, in _setup_lte
    await _login(hass, modem_data, password)
  File "/usr/src/homeassistant/homeassistant/components/tplink_lte/__init__.py", line 137, in _login
    await modem_data.modem.login(password=password)
  File "/usr/local/lib/python3.9/site-packages/tp_connected/tp_connected.py", line 130, in login
    await self.encryptCredentials(password, username)
  File "/usr/local/lib/python3.9/site-packages/tp_connected/tp_connected.py", line 114, in encryptCredentials
    _LOGGER.debug("ee: {0} nn: {1}".format(ee, nn))
UnboundLocalError: local variable 'nn' referenced before assignment

What version of Home Assistant Core has the issue?

core-2022-6-6

What was the last working version of Home Assistant Core?

No response

What type of installation are you running?

Home Assistant Supervised

Integration causing the issue

TP-Link LTE

Link to integration documentation on our website

https://www.home-assistant.io/integrations/tplink_lte/

Diagnostics information

No response

Example YAML snippet

tplink_lte:
  - host: local.ip.address.here
    password: !secret tplink_lte_password
    notify:
      - name: SMSGatewaySurname
        recipient: "+xxx"

Anything in the logs that might be useful for us?

No response

Additional information

No response