Answer by Devin Clark for I am getting an "Invalid Host header" message when connecting to webpack-dev-server remotely

Anyone coming here in 2021 on webpack-dev-server v4+,

allowedHosts and disableHostsCheck were removed in favor of allowedHosts: 'all'

To get rid of the error, change your devServer to this:

devServer: {  compress: true,  allowedHosts: 'all'}