On my Apple OS X (High Sierra system), I am trying to install a software called PowerPanel Business from CyberPower: it's a server that monitors an uninterruptable power supply (UPS) connected via USB, and allows management of it over an http interface. It installs fine without error.
On some of my machines, the access works via browser perfectly. On one machine, I try to go to the server's web page at "localhost:3052/agent/system_summary"
The browser says "Can't connect". How do I debug this? I know the process is running; how do I figure out why it's not able to serve its pages via http?