Server wont start up??

[JeffTheKnifer]

I made a spigot box server a while back, and now for whatever reason it just wont start up.

whenever anybody tried to join, it kicks them for "Unknown" and then gives this crash message:

io.netty.channel.AbstractChannel$AnnotatedConnectException:finishConnect(..) failed: Connection refused /***.25575

and that happens every time i try to join. sometimes it works, somehow but it ends up crashing after an hour or 2.

Anyone know what's up with this?

Edit: I just got the crash report from console: here that is also

 

java.util.ConcurrentModificationException
    at java.base/java.util.TreeMap$PrivateEntryIterator.nextEntry(TreeMap.java:1486)
    at java.base/java.util.TreeMap$KeyIterator.next(TreeMap.java:1540)
    at net.minecraft.world.level.TickListServer.b(TickListServer.java:70)
    at net.minecraft.server.level.WorldServer.doTick(WorldServer.java:438)
    at net.minecraft.server.MinecraftServer.b(MinecraftServer.java:1314)
    at net.minecraft.server.dedicated.DedicatedServer.b(DedicatedServer.java:438)
    at net.minecraft.server.MinecraftServer.a(MinecraftServer.java:1217)
    at net.minecraft.server.MinecraftServer.x(MinecraftServer.java:1050)
    at net.minecraft.server.MinecraftServer.lambda$0(MinecraftServer.java:305)
    at java.base/java.lang.Thread.run(Thread.java:833)

Edited November 20, 2022 by JeffTheKnifer

[Papycoima]

I believe it has something to do with the server.properties file, especially when you edit it. I had the same problem, and I fixed it by deleting the server.properties file and pasting in a new, untouched one from a brand new server.

Edited December 27, 2022 by Papycoima
clarity