Vue cli 3 hot reload suddenly not working in browsers

My problem was WDS
Console displayed:

[HMR] Waiting for update signal from WDS...
[WDS] Disconnected!
GET http://ip:port/sockjs-node/info?t=some-number
net::ERR_CONNECTION_TIMED_OUT sockjs.js?some-number

Solution for me was:
in

package.json

change

"serve": "vue-cli-service serve",

to

"serve": "vue-cli-service serve --host localhost",

or
add

module.exports = {
  devServer: {
    host: 'localhost'
  }
}

to

vue.config.js

🙂