How do I increase number of websocket clients in Nodejs Socket.io server deployed on AWS ECS fargate?

Question

I am running socket server container in AWS Fargate using socket.io

Everything works fine with connected users around 800-1000, But when the number of clients increases old socket connection gets disconnected automatically with error transport error.

My AWS ECS service(Fargate container) running behind AWS application load balancer.

Any specific configuration need to apply to support thousands of concurrent connection to my container?

Is there any limit of the number of concurrent users can connect to a single socket server?

AWS task definition has 4GB memory and 2 CPU

Socket server code:

io = module.exports = require('socket.io')(server, {
  'pingInterval': 10000,
  'pingTimeout': 7000,
  'origins': (env.APPLY_ALLOW_ORIGIN_FILTER) ? env.SOCKET_WHITELIST_URL : '*:*',
  transports: ['websocket', 'htmlfile', 'xhr-polling', 'jsonp-polling', 'polling']
})