Mss310 error
Hi, I cant get my mss310 working. 

My config is:

"accessories": [
        {
            "model": "MSS310",
            "name": "Meross Switch",
            "deviceUrl": "192.168.1.221",
            "channel": 0,
            "messageId": "1e28b96dd4e627b74ef96af0056da81d",
            "timestamp": 1589656230,
            "sign": "8d4fa1494ce548cd2c432483bff2d2f6",
            "accessory": "Meross"
        }

I have extracted the values ​​with the HTTP Catcher, but i get this error:

calling getOnCharacteristicHandler for MSS310 at 192.168.1.221...
(node:7160) UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'togglex' of undefined
    at Meross.getOnCharacteristicHandler (/homebridge/node_modules/homebridge-meross/index.js:297:41)
    at processTicksAndRejections (internal/process/task_queues.js:97:5)
(node:7160) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1)
(node:7160) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.


What I can do? Thank you
