Using JavaScript to connect sense to get data and report error

[hab]

When I use the API of the official website to retrieve the table data, an error is reported,as follows:

Error: unsupported certificate purpose
at TLSSocket.onConnectSecure (_tls_wrap.js:1049:34)
at TLSSocket.emit (events.js:182:13)
at TLSSocket._finishInit (_tls_wrap.js:631:8)
Emitted 'error' event at:
at ClientRequest.req.on (D:\workspase\weixin_app\node_modules\ws\lib\websocket.js:554:15)
at ClientRequest.emit (events.js:182:13)
at TLSSocket.socketErrorListener (_http_client.js:391:9)
at TLSSocket.emit (events.js:182:13)
at emitErrorNT (internal/streams/destroy.js:82:8)
at emitErrorAndCloseNT (internal/streams/destroy.js:50:3)
at process._tickCallback (internal/process/next_tick.js:63:19)

Here is my code:

var certPath =  path.join('D:','workspase','weixin_app','keys');
var certificates = {
    key: fs.readFileSync(path.resolve(certPath, 'client_key.pem')),
    cert: fs.readFileSync(path.resolve(certPath, 'client.pem')),
    root: fs.readFileSync(path.resolve(certPath, 'root.pem'))
};
const ws = new WebSocket('wss://172.16.100.74:4747/app/', {
    ca: [certificates.root],
    cert: certificates.cert,
    key: certificates.key,
    headers: {
        'X-Qlik-User':  'UserDirectory=internal; UserId=sa_engine'
    }
});
ws.onopen = function (event) {
    // send some message
}

any friends who know what the problem is？