How to fix a plugin that won't load on Cardboard

Cardboard supports many plugins but not all of them. Most failures can be traced from the console log.

Read the error

1. Start the server and scroll up to the first error mentioning the plugin's name.

2. Look at the type of message:

• Missing dependency: the plugin needs another plugin. Install that plugin and restart.
• Invalid plugin.yml or unsupported API: the jar may not be a real plugin, may be corrupted, or may target something Cardboard does not provide.
• Errors about internal server code (NMS) or missing classes: the plugin reaches into Minecraft internals or uses Paper-only features that Cardboard may not fully support.

Things to try

• Re-download the plugin jar in case the file is damaged.
• Check whether the plugin has a Spigot or Bukkit build. Plugins that stick to the standard API are the most likely to work, while Paper-specific or internals-heavy builds are the most likely to fail.
• Remove other plugins temporarily to rule out a conflict.
• Check the plugin's config for options that enable optional features, and turn off anything that needs unsupported functionality.

Still stuck?