In my build.gradle:

    "com.squareup.okhttp3:okhttp:3.13.1",
    'com.squareup.okhttp3:logging-interceptor:3.13.1',

Kotlin project open connect to websocket:

const val WEB_SOCKET_URL = "wss://api.lbkex.com/ws/V2/";

fun main(args: Array<String>) {

    val оkHttpClient = OkHttpClient()

    val wsListener = object : WebSocketListener() {
        override fun onOpen(ws: WebSocket, response: Response) {
            super.onOpen(ws, response)
             val requestJson = """{"action": "subscribe", "subscribe": "tick", "pair": "vtho_eth"}"""
             ws.send(requestJson)
        }

        override fun onClosing(webSocket: WebSocket, code: Int, reason: String) {
            super.onClosing(webSocket, code, reason)
            logger.info("ws Closing, reason = " + reason)
        }

        override fun onClosed(webSocket: WebSocket, code: Int, reason: String) {
            super.onClosed(webSocket, code, reason)
            logger.info("ws Closed")
        }

        override fun onFailure(webSocket: WebSocket, t: Throwable, response: Response?) {
            super.onFailure(webSocket, t, response)
            logger.error("ws Failure ", t)
        }

        override fun onMessage(webSocket: WebSocket, text: String) {
            super.onMessage(webSocket, text)
            logger.info("ws Text message: $text")
        }

        override fun onMessage(webSocket: WebSocket, bytes: ByteString) {
            super.onMessage(webSocket, bytes)

        }
    }

    logger.info("Started")
   val wsRequest = Request.Builder()
                   .url(WEB_SOCKET_URL)
                   .build()
     val ws = оkHttpClient.newWebSocket(wsRequest, wsListener)
}

As result I success open webscocket to wss://api.lbkex.com/ws/V2/.

As result method onMessage is call many times. Nice.

But after 15 minutes call method onFailure with error:

13:40:16.687 [OkHttp https://api.lbkex.com/...] ERROR MAIN_LOGGER - ws Failure
java.io.EOFException: null
        at okio.RealBufferedSource.require(RealBufferedSource.java:61)
        at okio.RealBufferedSource.readByte(RealBufferedSource.java:74)
        at okhttp3.internal.ws.WebSocketReader.readHeader(WebSocketReader.java:117)
        at okhttp3.internal.ws.WebSocketReader.processNextFrame(WebSocketReader.java:101)
        at okhttp3.internal.ws.RealWebSocket.loopReader(RealWebSocket.java:274)
        at okhttp3.internal.ws.RealWebSocket$2.onResponse(RealWebSocket.java:214)
        at okhttp3.RealCall$AsyncCall.execute(RealCall.java:206)
        at okhttp3.internal.NamedRunnable.run(NamedRunnable.java:32)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
        at java.lang.Thread.run(Unknown Source)