Server Sent Events using Laravel and Vue, After Five devices request the server, the server cup is going up to 90% and do not work anymore

This is my event stream code in vuejs. Everything work well, but when the users request more than 3 or 4 to the server. I am using Ubuntu Lightsail in Aws, The server's CPU is going up to 90% and cannot request to the server anymore. What is the problem ?

export default { name: "MarketStream", data() { return { marketdata: "", timestamp: "" }; }, created() { this.setupStream();

}, methods: { setupStream() { let es = new EventSource("/livemarketdata"); es.addEventListener( "message", event => { let data = JSON.parse(event.data); this.marketdata = data; // this.twoddata.push(data); }, false );

  es.addEventListener(
    "error",
    event => {
      if (event.readyState == EventSource.CLOSED) {
        console.log("Event was closed");
        console.log(EventSource);
      }
    },
    false
  );
},

} }