Why can't the Ruby on Rails application open at my_vps_ip:3000 on a VPS?

Question

Ruby on Rails

From the server's point of view, everything works fine and after executing the 'rails s' command, the RoR server writes that the application is running on port 3000 and invites you to go to http://localhost:3000.
Maybe you need to somehow open the port?
ISPmanager is installed on the VPS. Could it be that these are "tricks" of his firewall?

Answer 1

Because localhost is not accessible from the outside.
rails s -b 0.0.0.0