I downloaded the new Rocket.Chat 6.4.4 from tar.gz file (installing it as a service without docker)I and set up the service with the below environment variables: ROOT_URL="https://full.domain.name/" PORT=3001
The service is running but the web server shows three dots and trying to fetch files from http://localhost:3001/meteor/dynamic-import/fetch
I tried it with the following versions with the same results: 6.4.1 6.4.2 6.4.3
On version 4.6.3 the same configuration works as expected.
You might need to change the value in db. The value is set up at first launch and is set as source after that.
Src : https://www.ryadel.com/en/rocket-chat-change-root_url-site-url-rocketchat/?utm_content=cmp-true