Working on a local server but not on a hosted server

So I've created this plugin, but for some reason, saving and loading files is not going as planned on the remote server. It works perfectly on my local server, but not on the hosted server. Do you guys have any idea how this can happen?

I have the feeling I overlooked something incredibly stupid for this to happen...

Here's the github if case you want to see it: https://github.com/Akumasama/epicquest3/blob/master/src/randy/filehandlers/SaveLoader.java

 

Please describe in more detail what is not functioning. Does that plugin fail with an error? If so please share the stack trace.
What exactly is happening with the saved or loaded files, and what should be happening instead?

 

Alright. It seems to miss only certain points, it's very weird.
For some reason, it doesn't save the "Save_List" in the config. The player files only get saved the first time it seems, even though when I print information of when the saving is actually happening, it shows the new updated info. There is no stack trace, it would be handier if I got one of those. I'm basically clueless about what's happening.
I do see this line popping up all the time: "[Multicraft] Skipped x lines due to rate limit (30/s)". I'm not sure if this stops a certain progress or something?

 

Could it be a file permissions problem? Check if the files have read-only access. This would prevent them from being modified once created.