저는 도메인 서버를 열려고 이 유튜브를 모고 따라했어요:https://www.youtube.com/watch?v=SrjjwIieJ-g 

근데 ip6이나 ip4로는 열리고 도메인 주소로는 안 열려요. 그래서 server.properties 파일에 들어가 server.ip에다 포트를 적고 서버를 열어보니 cmd에서 

*** Error, this build is outdated ***

*** Please download a new build as per instructions from https://www.spigotmc.org/go/outdated-spigot ***

*** Server will start in 20 seconds ***

Loading libraries, please wait...

[13:19:43] [main/INFO]: Environment: authHost='https://authserver.mojang.com', accountsHost='https://api.mojang.com', sessionHost='https://sessionserver.mojang.com', name='PROD'

[13:19:44] [main/INFO]: Reloading ResourceManager: Default, bukkit

[13:19:46] [Worker-Main-4/INFO]: Loaded 7 recipes

[13:19:43] [main/INFO]: Environment: authHost='https://authserver.mojang.com', accountsHost='https://api.mojang.com', sessionHost='https://sessionserver.mojang.com', name='PROD'

[13:19:44] [main/INFO]: Reloading ResourceManager: Default, bukkit

[13:19:46] [Worker-Main-4/INFO]: Loaded 7 recipes

[13:19:52] [Server thread/INFO]: Starting minecraft server version 1.16.1

[13:19:52] [Server thread/INFO]: Loading properties

[13:19:55] [Server thread/INFO]: This server is running CraftBukkit version git-Spigot-0287a20-7560f5f (MC: 1.16.1) (Implementing API version 1.16.1-R0.1-SNAPSHOT)

[13:19:55] [Server thread/INFO]: Server Ping Player Sample Count: 12

[13:19:55] [Server thread/INFO]: Using 4 threads for Netty based IO

[13:19:55] [Server thread/INFO]: Debug logging is disabled

[13:19:55] [Server thread/INFO]: Default game type: SURVIVAL

[13:19:55] [Server thread/INFO]: Generating keypair

[13:19:55] [Server thread/INFO]: Starting Minecraft server on 0411seannnisbbabbo.kro.kr:25565

[13:19:55] [Server thread/INFO]: Using default channel type

[13:20:01] [Server thread/WARN]: **** FAILED TO BIND TO PORT!

[13:20:01] [Server thread/WARN]: The exception was: java.net.BindException: Cannot assign requested address: bind

[13:20:01] [Server thread/WARN]: Perhaps a server is already running on that port?

[13:20:01] [Server thread/INFO]: Stopping server

[13:20:01] [Server thread/INFO]: Saving players

[13:20:01] [Server thread/INFO]: Saving worlds

>계속하려면 아무 키나 누르십시오 . . .

이런게 뜨더라구요.