websocket_api script: Error executing script

I have tried to use this integration already few times, and all of them has failed. Today I had some more time so I tried to gather some logs.

How the setup is made as for now:

router is TP-Link MR6400
v5.3
as I found in few places for testing purposes router and HA are placed in same LAN (same IP pool),
local management is allowed via port 80 (no any IP whitelisting),
from same source (if I address PC to HomeAssistant IP for tests) I am able to login to TP-Link portal
during testing I am logged out of the gui (as it was reported to interrupt tp-link API)
I have droppped packets from tp-link facing port and packets from HA while calling notify service are visible

But the service falls by itself, I can see errors:

Logger: custom_components.mr6400sms.devices.router
Source: custom_components/mr6400sms/devices/router.py:53
Integration: mr6400sms ([documentation](https://github.com/cziter15/ha-tplink-mr6400-sms-notify), [issues](https://github.com/cziter15/ha-tplink-mr6400-sms-notify/issues))
First occurred: 18:52:23 (2 occurrences)
Last logged: 18:52:24

    Retrying login (1 of 3) due to exception {Invalid encryption key request because of status 500}
    Retrying login (2 of 3) due to exception {int() can't convert non-string with explicit base}

Logger homeassistant.helpers.script.websocket_api_script
Source: custom_components/mr6400sms/devices/mr6400.py:96
Integration: mr6400sms ([documentation](https://github.com/cziter15/ha-tplink-mr6400-sms-notify), [issues](https://github.com/cziter15/ha-tplink-mr6400-sms-notify/issues))
First occurred: 18:52:25 (1 occurrences)
Last logged: 18:52:25
websocket_api script: Error executing script. Unexpected error for call_service at pos 1: Token is missing. Please login first.

Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 468, in _async_step
    await getattr(self, handler)()
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 704, in _async_call_service_step
    response_data = await self._async_run_long_action(
                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/helpers/script.py", line 666, in _async_run_long_action
    return long_task.result()
           ^^^^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/core.py", line 1969, in async_call
    response_data = await coro
                    ^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/core.py", line 2006, in _execute_service
    return await target(service_call)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/components/notify/legacy.py", line 264, in _async_notify_message_service
    await self.async_send_message(**kwargs)
  File "/config/custom_components/mr6400sms/notify.py", line 28, in async_send_message
    await self.router_client.send_message(phone_numbers, message)
  File "/config/custom_components/mr6400sms/devices/router.py", line 71, in send_message
    await self._send_sms(phone, message)
  File "/config/custom_components/mr6400sms/devices/mr6400.py", line 96, in _send_sms
    raise RouterException("Token is missing. Please login first.")
custom_components.mr6400sms.devices.router.RouterException: Token is missing. Please login first.

cziter15 / ha-tplink-mr6400-sms-notify

websocket_api script: Error executing script #2