Web Socket Error 406
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### What issue do you have? Please be as thorough and explicit as possible.

Getting the below errors in my HomeBridge log - the two warnings repeat about every 3 minutes. The sequence number changes every time. The plugin is working fine, devices are controllable and responding correctly in the Home app

### Details of your setup.
* Do you use (1) Homebridge (+ config-ui), (2) Homebridge (CLI) or (3) HOOBS? 

HomeBridge (1.3.0) + config-ui (4.39.0) + Docker (Synology NAS)

* Which version of Homebridge/HOOBS do you have?

HomeBridge 1.3.0

* Which platform do you run Homebridge/HOOBS on (e.g. Raspberry Pi/Windows/HOOBS Box)? Please also mention your version of Node.js/NPM if known.

npm 16.14.10
node.js 14.15.5

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

eWeLink plugin version 4.7.6

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

2x Sonoff Micro USB Smart Adapters

### Please paste any relevant logs below.

```
[2/22/2021, 11:05:10 AM] [eWeLink] WS login failed as Unknown WS parameters received
{
  "error": 406,
  "apikey": "2a9c7a8f-REDACTED",
  "sequence": "1613991910244",
  "actionName": "userOnline"
}{.
[2/22/2021, 11:05:10 AM] [eWeLink] WS unknown command received.
{
  "error": 406,
  "apikey": "2a9c7a8f-REDEACTED",
  "sequence": "1613991910244",
  "actionName": "userOnline",
  "params": {}
}
```