I think you might want to set your root URL to your domain and make sure it resolves correctly. It could be a local private domain, or a public one, but it must resolve correctly.
Note: You must use the outside https address for the value at ROOT_URL in [[Section 3|Deploy-Rocket.Chat-without-docker#3-download-rocketchat]] above. This includes the https:// and leave off the port number. So instead of ROOT_URL=http://localhost:3000 use something like https://your_hostname.com