If you find your server crashing or not starting up with the following error showing in the console and crash logs:
java.lang.NullPointerException: Exception in server tick loop
This error message typically means that there is an issue or corruption with one of your ops.json or whitelist.json files.
The following steps will guide you on fixing this issue:
Step 1. Stop your server
Step 2. Access your servers files using FTP and delete the ops.json and whitelist.json files or replace them with a backup copy of these files
Step 3. Start your server
If you have any difficulties with following this guide, or any other issues with your server, please open a ticket with our Minecraft Technical Support Team.