If your server won't start and is displaying this error:
java.lang.NullPointerException: Exception in server tick loop
This means there is an issue with a core JSON file.
To fix this error:
- Stop your server
- Access your server's files through FTP
- Validate the ops.json, whitelist.json, and usercache.json files by pasting them into a validator here
- Fix any errors and replace the old files with the corrected files
- Restart the server
If that doesn't fix the issue, contact us through a support ticket.