zero downtime width loadBalancing is not working?

[ddaydd]

hello everyone, can you help me? how can we verify that the load balancing is working well? i have three servers with proxy.loadBalancing: true , and the zero downtime is not working... thanks

Mup version 1.5.3:

Mup config

{
  "servers": {
    "one": {
      "host": "1.2.3.4",
      "username": "root",
      "password": "password"
    },
    "two": {
      "host": "1.2.3.4",
      "username": "root",
      "password": "password"
    },
    "three": {
      "host": "1.2.3.4",
      "username": "root",
      "password": "password"
    }
  },
  "proxy": {
    "domains": "subdomain.host.com,subdomain.host.com,subdomain.host.com",
    "shared": {
      "httpPort": 80
    },
    "clientUploadLimit": "0",
    "ssl": {
      "letsEncryptEmail": "email@domain.com",
      "forceSSL": true
    },
    "loadBalancing": true,
    "stickySessions": true
  },
  "app": {
    "name": "my-app",
    "path": "../",
    "servers": {
      "one": {},
      "two": {},
      "three": {}
    },
    "buildOptions": {
      "serverOnly": true
    },
    "volumes": {
      "/opt/dfm-files": "/opt/dfm-files"
    },
    "env": {
      "PORT": 4002,
      "ROOT_URL": "https://subdomain.host.com",
      "MONGO_URL": "mongodb://user:pass@subdomain.subdomain.host.com:27017",
      "VIRTUAL_HOST": "subdomain.host.com,subdomain.host.com,subdomain.host.com",
      "HTTPS_METHOD": "redirect",
      "LETSENCRYPT_HOST": "subdomain.host.com,subdomain.host.com,subdomain.host.com",
      "LETSENCRYPT_EMAIL": "email@domain.com",
      "VIRTUAL_PORT": 3000,
      "HTTP_FORWARDED_COUNT": 1
    },
    "docker": {
      "image": "abernix/meteord:node-12.14.0-base",
      "prepareBundle": true,
      "stopAppDuringPrepareBundle": false,
      "useBuildKit": true,
      "imagePort": 3000
    },
    "enableUploadProgressBar": true,
    "deployCheckWaitTime": 120,
    "type": "meteor"
  }
}