Here's the crash report.

https://pastebin.com/vPCZkUCS

The main line of interest in the crash report is probably :
at net.minecraft.server.MinecraftServer.handler$cci000$carpet$modifiedRunLoop(MinecraftServer.java:8394)

It should be noted that I have c2me installed as well as starlight. I also have 300+ other mods installed as well though.

Please see #1747.

In a nutshell: it was one of the other 300+ mods you have.

By the nature of the error (watchdog) we can't really tell you much about it, something was deadlocked or in an infinite loop.

I'll look into it more. Thanks. I'll close this for now.

Seems my actual server itself, not the MC server, but the machine running it was running out of memory which was causing it. Nice.