for info-beamer hosted
See “Expose info-beamer ports” in the documentation.
for info-beamer pi
The most likely reason is, that info-beamer by default is only reachable from the local machine. This prevents it from being accidentally exposed to the internet by accident. If you want info-beamer to be reachable from anywhere, just set the environment variable
To verify that a connection is possible, you can use telnet to connect to info-beamer on port 4444 like this:
$ telnet <ip-of-info-beamer> 4444
You should get a info-beamer hello message.