My minecraft server doesn't work?

(I'm using a MacBook Air) When I press start.command, everything seems normal, like it usually do. But, in Minecraft, it looks like the server isn't running (in the multiplayer page) and when I try to join it it says "host is down", and I have portforwarded it, it worked perfectly a week ago. Any solution?

Try making a new server, if that works and you want the other world that you had then switch the worlds