"You cannot be reached from outside"

In ‘System status’ tab I get this message from time to time, I don’t think this is a port issue because if it were it should always show that message, right? And what happens is that sometimes I’m in senior mode, and some times I “cannot be reached” and so on. Sometimes I can fix it by restarting the server but it doesn’t always work.

A sidequestion I would like to ask is, in this state (when I got the “You cannot be reached from outside” message) is it worth to continue crawling? because if I “cannot be reached from outside” it seems worthless to be using computer resources for indexing sites that no one is going to be able to potentially visit.

PD: I’m not using any VPN and I’m on Linux.