Minecraft server fails on Pi: java.lang.NullPointerException: null

I decided to start up my minecraft server today after a period of inactivity. I was greeted with these errors a minute after starting. I’ve seen this question that claims this is an issue with the Java version, but I just updated it to the latest release for Raspberry Pi.

$ java -version
openjdk version "11.0.8" 2020-07-14
OpenJDK Runtime Environment (build 11.0.8+10-post-Raspbian-1deb10u1)
OpenJDK Server VM (build 11.0.8+10-post-Raspbian-1deb10u1, mixed mode)

● minecraft.service - Minecraft Server
   Loaded: loaded (/etc/systemd/system/minecraft.service; disabled; vendor preset: enabled)
   Active: inactive (dead) since Sat 2021-01-09 20:07:57 EST; 37s ago
  Process: 21630 ExecStart=/usr/bin/java -Xmx768M -Xms512M -jar server.jar nogui (code=exited, status=0/SUCCESS)
  Process: 21827 ExecStop=/opt/minecraft/tools/mcrcon/mcrcon -H 127.0.0.1 -P 25575 -p [REMOVED] stop (code=exited, status=1/FAILURE)
 Main PID: 21630 (code=exited, status=0/SUCCESS)
   CGroup: /system.slice/minecraft.service
           └─15131 /usr/bin/java -Xmx768M -Xms512M -jar server.jar nogui

Jan 09 20:07:56 raspberrypi java[21630]: java.lang.NullPointerException: null
Jan 09 20:07:56 raspberrypi java[21630]:         at net.minecraft.server.MinecraftServer.a(SourceFile:546) ~[server.jar:?]
Jan 09 20:07:56 raspberrypi java[21630]:         at net.minecraft.server.MinecraftServer.m(SourceFile:574) ~[server.jar:?]
Jan 09 20:07:56 raspberrypi java[21630]:         at uk.m(SourceFile:593) ~[server.jar:?]
Jan 09 20:07:56 raspberrypi java[21630]:         at net.minecraft.server.MinecraftServer.run(SourceFile:676) [server.jar:?]
Jan 09 20:07:56 raspberrypi java[21630]:         at java.lang.Thread.run(Thread.java:834) [?:?]
Jan 09 20:07:57 raspberrypi systemd[21827]: Failed to attach 21827 to compat systemd cgroup /system.slice/minecraft.service: No such file or directory
Jan 09 20:07:57 raspberrypi mcrcon[21827]: Connection failed.
Jan 09 20:07:57 raspberrypi mcrcon[21827]: Error 111: Connection refused
Jan 09 20:07:57 raspberrypi systemd[1]: minecraft.service: Succeeded.