[19:53:17 FATAL]: Failed to start the minecraft server
net.minecraft.server.v1_16_R3.SessionLock$ExceptionWorldConflict: /root/server/./world/session.lock: already locked (possibly by other Minecraft instance?)
        at net.minecraft.server.v1_16_R3.SessionLock$ExceptionWorldConflict.a(SourceFile:98) ~[patched_1.16.5.jar:git-Paper-794]
        at net.minecraft.server.v1_16_R3.SessionLock.a(SourceFile:44) ~[patched_1.16.5.jar:git-Paper-794]
        at net.minecraft.server.v1_16_R3.Convertable$ConversionSession.<init>(Convertable.java:257) ~[patched_1.16.5.jar:git-Paper-794]
        at net.minecraft.server.v1_16_R3.Convertable.c(Convertable.java:227) ~[patched_1.16.5.jar:git-Paper-794]
        at net.minecraft.server.v1_16_R3.Main.main(Main.java:154) ~[patched_1.16.5.jar:git-Paper-794]
        at org.bukkit.craftbukkit.Main.main(Main.java:289) ~[patched_1.16.5.jar:git-Paper-794]
        at jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103) ~[?:?]
        at java.lang.reflect.Method.invoke(Method.java:580) ~[?:?]
        at io.papermc.paperclip.Paperclip.main(Paperclip.java:58) ~[server.jar:?]