Why does not my Minecraft server start over public IP address?

So I want to play with my friend in my Minecraft Server together. The Minecraft server is started directly from my PC, and since I and my friend live far apart, I have to try to publish my Minecraft server by typing "How is my IP" and my public IP so that my friend on my server can access. But after I entered the public IP in Config, the server quits itself.

[18:03:14] [Server thread / INFO]: Starting minecraft server version 1.12
[18:03:14] [Server thread / INFO]: Loading properties
[18:03:14] [Server thread / INFO]: Default game type: SURVIVAL
[18:03:15] [Server thread / INFO]: This server is running CraftBukkit version git-spigot-ede465d-bb4ae3b (MC: 1.12) (Implementing API version 1.12-R0.1-SNAPSHOT)
[18:03:15] [Server thread / INFO]: Debug logging is disabled
[18:03:15] [Server thread / INFO]: Server Ping Player Sample Count: 12
[18:03:15] [server thread / INFO]: Using 4 threads for Netty based IO
[18:03:15] [server thread / INFO]: Generating keypair
[18:03:15] [Server thread / INFO]: Starting Minecraft server on [My IP]
[18:03:15] [Server thread / INFO]: Using default channel type
[18:03:15] [Server thread / WARN]: FAILED TO BIND TO PORT!
[18:03:15] [server thread / WARN]: The exception was: java.net.BindException: Can't assign requested address: bind
[18:03:15] [server thread / WARN]: Perhaps a server is already running on that port?
[18:03:15] [Server thread / INFO]: Stopping server
[18:03:15] [Server thread / INFO]: Saving players

You should not set a fixed IP in the config.

By the way, "FAILED TO BIND TO PORT" means that the port may already be busy.

Did you open the port in the router?

You still need to unlock your port. You can go to your port by going to your router's website or router settings and going to port sharing or whatever, and you need to unlock the port via TCP and UDP at 25565. You have to synonymous if necessary. If it does not work under Windows Firewall also unlock.

Yes, I prefer nothing to optimize with router, because the router is not mine but my father and there it can be annoying.

No, so I will not trust in the router what to ask, otherwise I get worse with my dad.

Is there an alternative?

You have to open the ports, otherwise there's nothing.

Hamachi.

Do I have to install Hamachi at my friend's or is it enough for me to have Hamachi?

But otherwise I get worse from my father.

Without it is not possible!

Then a paid server would be a solution.

Your friend and you must have hamachi installed

You probably have the port already running. You also might need to port forward on your router.