According to the reference providing a value of 0 to the port argument of startup() is supposed to assign a random avaliable port to the new world. Currently doing this will cause the new world to attempt to start on the last port used, even if it's not open. And the following error appears in the Daemon window:
BYOND hub reports port 0 cannot be reached by players.
The code to reproduce it is simple:
When does the problem NOT occur?