When I start my server, I get this error every few seconds:
java.lang.NullPointerException: Cannot invoke "net.creeperhost.ftbbackups.data.Backup.isProtected()" because "backup" is null at TRANSFORMER/[email protected]/net.creeperhost.ftbbackups.data.Backups.lambda$unprotectedSize$0(Backups.java:22) at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:178) at java.base/java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1625) at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:509) at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499) at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:575) at java.base/java.util.stream.AbstractPipeline.evaluateToArrayNode(AbstractPipeline.java:260) at java.base/java.util.stream.ReferencePipeline.toArray(ReferencePipeline.java:616) at java.base/java.util.stream.ReferencePipeline.toArray(ReferencePipeline.java:622) at java.base/java.util.stream.ReferencePipeline.toList(ReferencePipeline.java:627) at TRANSFORMER/[email protected]/net.creeperhost.ftbbackups.data.Backups.unprotectedSize(Backups.java:22) at TRANSFORMER/[email protected]/net.creeperhost.ftbbackups.BackupHandler.clean(BackupHandler.java:369) at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:539) at java.base/java.util.concurrent.FutureTask.runAndReset(FutureTask.java:305) at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:305) at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136) at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) at java.base/java.lang.Thread.run(Thread.java:833)
This message only appears in the console and not in the logs for whatever reason, but it completely disables the backups.

Issue fixed after reinstalling the server without changing anything else