Issue with LAN control
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### What issue do you have? Please be as thorough and explicit as possible.

When there is no internet connection, and I restart homebridge, the plugin cannot discover the devices and they cannot be controlled from Home app.

They can be controlled from the ewelink app in LAN mode
### Details of your setup.
* Do you use Homebridge (with config-ui?) or HOOBS? 
Homebridge with config-ui


* Which version of Homebridge/HOOBS do you have?

1.3.4

* Which version of this plugin (homebridge-ewelink) do you have? Has the issue started since upgrading from a previous version?

V6.6.0 - Not sure.

* Which eWeLink devices do you have that are causing issues? Please include product models if applicable.

Multiple TX1/2/3 gang US version switches.
Multiple POWR2 switches.
Basically all ewelink devices in the home

* Do you use your main eWeLink credentials or do you use a secondary eWeLink account for Homebridge?
Main Ewelink


### Please paste any relevant logs below.
Config:

   {
            "name": "eWeLink",
            "username": "email",
            "password": "password",
            "language": "en",
            "mode": "auto",
            "singleDevices": [
                {
                    "deviceId": "ID",
                    "label": "Kitchen Lights",
                    "ipAddress": "192.168.1.92"
                },
                {
                    "deviceId": "ID",
                    "label": "Front Balcony Lights",
                    "ipAddress": "192.168.1.86"
                },
                {
                    "deviceId": "ID",
                    "label": "Rear Balcony Lights",
                    "ipAddress": "192.168.1.82"
                },
                {
                    "deviceId": "ID",
                    "label": "Living Lights",
                    "ipAddress": "192.168.1.85"
                },
                {
                    "deviceId": "ID",
                    "label": "Bedroom UPS Lights",
                    "ipAddress": "192.168.1.89"
                }
            ],
            "multiDevices": [
                {
                    "deviceId": "ID",
                    "label": "Bedroom Lights",
                    "ipAddress": "192.168.1.91"
                },
                {
                    "deviceId": "ID",
                    "label": "Hallway/Living UPS Lights",
                    "ipAddress": "192.168.1.87"
                },
                {
                    "deviceId": "ID",
                    "label": "Hallway Lights",
                    "ipAddress": "192.168.1.88"
                }
            ],
            "outletDevices": [
                {
                    "deviceId": "ID",
                    "label": "Bedroom AC",
                    "ipAddress": "192.168.1.93"
                },
                {
                    "deviceId": "ID",
                    "label": "Living AC",
                    "ipAddress": "192.168.1.80"
                },
                {
                    "deviceId": "ID",
                    "label": "Water Pump",
                    "ipAddress": "192.168.1.83"
                },
                {
                    "deviceId": "ID",
                    "label": "Heater",
                    "ipAddress": "192.168.1.84"
                }
            ],
            "thDevices": [
                {
                    "deviceId": "ID",
                    "label": "Pool Temperature",
                    "hideSwitch": true,
                    "offset": 0.5,
                    "minTarget": 10,
                    "maxTarget": 40
                }
            ],
            "platform": "eWeLink"
        }

```

```
